A Balclutha man drowned in a river near his house after he was processed for drink driving and dropped home by police, a coroner has ruled.

Michael Dippie was known to be a heavy drinker and his former partner had said he was depressed, although he had never been treated or diagnosed for depression.

Police believed Dippie took his own life, but coroner David Crerar said that alternative scenarios could not be ruled out.

Dippie drowned after "accidentally or deliberately" entering the Clutha River the night of October 29 or in the early hours of October 30, Crerar ruled in his findings, released today.

The 55-year-old's body was found partially submerged in the river more than two weeks later.

Dippie was stopped at a police check point in Balclutha on the evening of October 29, 2011.

He was processed for drink driving and taken to the police station for a breath test. An officer then dropped him at his home, where he watched Dippie walk up the driveway.

He was the last person to see Dippie alive.

Dippie wasn't unfamiliar to police. He had been processed for drink driving in the past and had spent time in prison for drink driving offences.

In 2005, after being processed for drink driving, police found him at the Clutha River Bridge, where he threatened to jump. Police convinced him to go home and later learnt that he spent the next five days in bed with depression.

A woman who had been in a long term relationship with Dippie said she now recognised Dippie had suffered from depression, Crerar said in his report.

She said his depression was exacerbated by the death of his mother but did not think that he had ever sought professional help for his depression or alcoholism.

While suicide was a possibility Crerar said he was not confident that Dippie had taken his own life.

"His actions and behaviour...was similar to the behaviour exhibited earlier in 2005 when he was charged with excess breath alcohol driving offences. This similarity is, in itself however, insufficient to persuade me that the death of Michael Dippie was indeed a suicide," he said.

"In the absence of direct observation, by any person, of Michael Dippie deliberately entering the river.

- © Fairfax NZ News