Tense final day at Nicky Stevens' coronial inquest

It was a tense final day at the coronial inquest into the death of mental health patient Nicky Stevens - who was allowed to leave a Hamilton facility without supervision.

His parents gave evidence on Friday and clashed with the lawyer of the psychiatrist who let him leave.

Mr Stevens walked out of Hamilton's Henry Bennett Centre in March 2015 for a smoke, which was allowed. His body was found the Waikato River three days later.

Mr Steven's father, Dave MacPherson, took the stand for the first time today. But things got heated when he was cross-examined by the lawyer representing the psychiatrist who cared for Mr Stevens at the centre.

The psychiatrist had allowed the 21-year-old to have two 15-minute breaks, unescorted. They said that was decided at a meeting the parents were at, three days before his disappearance.

But Mr Stevens' parents dispute that.

"We were never going to discuss Nicky's unescorted leave - which he wanted - in front of him," they say.

The inquest heard the psychiatrist knew the parents wanted to be involved with decisions about their son, but had to weigh that up with the wishes Mr Stevens expressed saying he didn't want them consulted.

The psychiatrist said allowing Mr Stevens to leave for smoke breaks was part of his recovery.

He was admitted with acute psychosis after a serious suicide attempt about three weeks before his body was found in the Waikato River.

His mother, Jane Stevens, hopes there will greater collaboration between clinicians and whanau as a result of the inquest.

"And in that way we can honour our son and other children who have been lost in that way in this way," she says.

Coroner Wallace Bain is expected to release his findings later this year.