A lawyer for Waitemata District Health Board has told the High Court a smoking ban at its Auckland hospitals is lawful.
Two former psychiatric patients and a retired nurse are challenging the ban saying it breaches the Bill of Rights. Smoking has prohibited on all the DHB's sites since 2009.
Lawyer for the DHB Jonathon Coates told the court on Tuesday that 4700 New Zealanders die each year from smoking-related illnesses, 400 of them from second-hand smoke.
He says its ban demonstrates it is a healthcare leader and is following the Government's strategy to reduce those fatalities.
"It's a policy decision made by the district health board. The court should be reluctant to intervene in policy decisions - particularly where they're made, as here, on highly technical issues by the experts in the field."
Mr Coates says the Smokefree Environment Act gives it the right to decide whether to have dedicated smoking areas, so it is acting lawfully.
He argues the DHB's smoking ban is no different from bans on alcohol, gambling, pornography or sexual relationships within hospitals.
"You can't gamble in mental health, you can't have sexual relations with people in the facility, you can't access pornographic material in there.
"There are a whole range of things that these people might say that they could do when they're out and in the freedom of their own home that they can do lawfully, but you can't do it when you're in the hospital."
Jonathon Coates says courts elsewhere have previously rejected challenges to smoking bans at hospitals. These include the Court of Appeal in England, which rejected a challenge to a smoking ban at a hospital's mental health unit in 2007.
Mr Coates also read from a joint report released earlier this year by Britain's Royal Colleges of Psychiatry and Physiology which says patients often get their mental health and tobacco withdrawal symptoms confused.
It went on to say that the effect of smoking on health is enough to justify a total prohibition at health care facilities.
The judge is expected to reserve his decision.