On 12 November 2014, the High Court of Australia (the High Court) handed down its decision in Hunter and New England Local Health District v Merryn Elizabeth McKenna; Hunter and New England Local District Health v Sheila Mary Simon & Anor [2014] HCA 44, in which it considered the tension between common law duties and statutory obligations.

A patient with a history of paranoid schizophrenia was discharged from hospital into the care of a friend to drive him from Taree in New South Wales to his hometown, Echuca in Victoria where it was planned that he would access ongoing mental health treatment.  Tragically during the journey, the former patient killed his friend.  The relatives of the deceased sought damages for psychiatric injuries they suffered upon learning of the death.

The High Court unanimously found that no relevant duty was owed.  This case highlights the tension that can exist between common law duty and statutory obligation and the difficulties that can arise as a consequence for plaintiffs when there is an inconsistency between such duty and obligation.   


Mr Phillip Pettigrove was a chronic paranoid schizophrenic.  He was receiving treatment for his illness in Echuca, Victoria. 

In July 2004, Mr Pettigrove was in New South Wales where he was admitted as an involuntary patient to Manning Base Hospital in Taree (the Hospital).  Mr Pettigrove was accompanied by his friend, Mr Stephen Rose.  Dr Warwick Coombes, psychiatrist and Dr Kay Wu, medical superintendent of the Hospital, were of the opinion that Mr Pettigrove was a ‘mentally ill person’ and ought to be detained pursuant to the provisions of the Mental Health Act 1990 (NSW) (the Mental Health Act).  

After reviewing Mr Pettigrove’s medical records obtained from the Echuca Community Mental Health Service and consultation with Mr Pettigrove, Mr Pettigrove’s mother and Mr Rose, the Hospital decided that Mr Pettigrove could be discharged the following day, at which time Mr Rose would drive Mr Pettigrove to his mother’s home in Echuca. 

On the journey back to Echuca, Mr Pettigrove killed Mr Rose and subsequently took his own life.

On first instance

Mr Rose’s relatives (the relatives) commenced two separate proceedings in the District Court of New South Wales against Hunter and New England Local Health District (the Health Authority) for damages for psychiatric injury suffered as a result of Mr Rose’s death.  As the claims were not materially different, the proceedings were jointly heard. 

The trial judge found there was no breach of duty and entered judgment in favour of the Health Authority.  When deciding the matter, the trial judge considered section 5B of the Civil Liability Act 2002 (NSW) (the Civil Liability Act) and held that it was not necessary to show that: … a reasonable person in Dr Coombes’ position would have concluded that there was a not insignificant risk of Mr Pettigrove behaving as he did.  The trial judge further held that section 5O of the Civil Liability Act applied where Dr Coombes had acted: … in a manner that (at the time the service was provided) was widely accepted in Australia by peer professional opinion as competent professional practice

The Court of Appeal

The relatives appealed the decision to the Court of Appeal of the Supreme Court of New South Wales.  The Court of Appeal held that the Hospital Authority: … owed Mr Rose a common law duty to take reasonable care to prevent Mr Pettigrove causing physical harm to Mr Rose and that by discharging Mr Pettigrove, the Hospital Authority was negligent.  On this basis, the Court of Appeal ordered judgment in favour of the relatives.

The High Court of Australia

The Health Authority (the appellant) was granted special leave to appeal to the High Court in each matter.  Whilst the appellant appealed on a number of grounds, the High Court ordered that oral submissions only be made on the issue of duty of care.  The High Court held that issues as to breach of duty, competent professional practice, liability for breach of a statutory duty and the special statutory powers were only to be examined if it could be established that the appellant owed the respondent a relevant duty of care. 

Duty of Care

The High Court acknowledged the difficulties in determining the existence of a duty of care by reference to Sullivan v Moody (2001) 207 CLR 562 (‘Sullivan’).  In Sullivan, the court identified four examples where problems arose in identifying a duty of care, namely, the nature of harm, the exercise of statutory powers and discretions, the indeterminacy of class and coherence. 

The High Court held that all these problems applied in the relatives’ claim that the appellant owed them a: … duty to take reasonable care when deciding that the powers given by the Mental Health Act, which had been used to detain Mr Pettigrove, should no longer be used to prevent him leaving the Hospital.  In particular, the relatives alleged that: (1) the appellant should not have discharged Mr Pettigrove and (2) the appellant should not have allowed Mr Pettigrove to leave in the company of Mr Rose due to the risk that Mr Pettigrove may physically injure Mr Rose. 

The High Court expressed the view that the difficulty in identifying whether the appellant owed the relatives a duty of care, stemmed from the apparent inconsistency in the duties of the appellant under the Mental Health Act and common law.  

Mental Health Act

Under section 20 of the Mental Health Act detention, or the continuation of detention, of a mentally ill person: … unless the medical superintendent is of the opinion that no other care of a less restrictive kind is appropriate and reasonably available to the person is prohibited.  Consequently, the High Court held that when involuntarily admitting or detaining a person, a medical superintendent must consider whether a person is a mentally ill person or mentally disordered person and if so, is no other care of a less restrictive kind, which is appropriate and reasonably available to the person?

In interpreting section 20 and the other provisions of the Mental Health Act, the appellant must have regard to section 4(2)(b), which states:

It is the intention of Parliament that the provisions of this Act are to be interpreted and that every function, discretion and jurisdiction conferred or imposed by this Act is, as far as practicable, to be performed or exercised so that: 

  1.         …
  2. in providing for the care and treatment of persons who are mentally ill        or who are mentally disordered, any restriction on the liberty of patients        and other persons who are mentally ill or mentally disordered and any        interference with their rights, dignity and self-respect are kept to the        minimum necessary in the circumstances.

It follows that in making any decisions related to the care of a mentally ill person, the appellant must endeavour to ensure that interference with the: … rights, dignity and self-respect are kept to the minimum necessary in the circumstances.  Consequently, a determination that a person is a ‘mentally ill person’ does not automatically render it appropriate that the mentally ill person be involuntarily admitted and detained. 

The Mental Health Act has been repealed and replaced with the Mental Health Act 2007 (NSW).

Inconsistent Duties

The inconsistency between the duties of the appellant under the Mental Health Act and common law is apparent.  Under the common law, performance of the appellant’s duty of care towards Mr Pettigrove would have required the appellant to have regard to: … the interests of those, or some of those, with whom the mentally ill person may come in contact when not detained.  The High Court explained this duty as follows.  If a hospital was to owe a duty of care to those with whom a mentally ill person may come in contact after discharge to protect them from the risk of harm, the hospital would need to consider whether the risk of harm is foreseeable and not insignificant.  The risk that a mentally ill person may behave irrationally can be appropriately regarded as both foreseeable and not insignificant.  A reasonable precaution to avoid this risk would be to continue to detain that person for a longer period of time until the hospital is satisfied that the person no longer poses a risk.  However, this is inconsistent with the duties of a hospital under the Mental Health Act.

The Mental Health Act requires that the period of involuntary detainment be kept at a minimum so as not to interfere with the liberty of a mentally ill person.  If a medical superintendent is of the view that care of a less restrictive kind was appropriate and reasonably available to a mentally ill person, the medical superintendent (and hospital) is required to discharge that person as soon as practicable.  It was pursuant to section 20 of the Mental Health Act that the appellant released Mr Pettigrove, on the opinion of its medical superintendent that less restrictive care was appropriate and available to Mr Pettigrove.  


The High Court held that the appellant, being the Hospital and its staff, did not owe a relevant duty of care to the relatives as alleged.  The appellant acted with regard to its powers, duties and responsibilities in relation to the involuntary admission and detention of mentally ill persons pursuant to the provisions of the Mental Health Act.  The High Court opined that these: ... provisions are inconsistent with finding the common law duty of care alleged by the relatives.  As a result, it was held unnecessary to consider the: … extent and potential indeterminacy of liability of liability which imposing a duty of care would entail. 

This case, like a number that have gone before it, highlights the need that when determining the nature and scope of a duty of care in particular circumstances regard must be had to the statutory framework, which may serve to circumscribe, limit or over-ride the duty otherwise owed.