The drowning of a "grossly intoxicated" man demonstrates alcohol and water don't mix, a coroner says.
Christopher Perreau died while trying to swim across the mouth of the Mokihinui River in the Buller District in January last year.
Coroner Richard McElrea stated in his findings that Mr Perreau, 44, had a blood alcohol level of 228mg per 100ml of blood, nearly three times the legal driving limit for someone his age.
Mr Perrau, who was with three friends and some children, was swimming back from the southern bank of the river when one of his friends noticed him go under the water.
After he failed to resurface, the friend called for help and unsuccessfully tried to dive down and rescue him.
"A rescue helicopter discovered him a short time later in about 2-2.5 metres of water approximately 100 metres from where he had entered the water. He was unable to be revived," Coroner McElrea said.
The weather at the time was fine and the river was calm.
While evidence from witnesses failed to disclose how Mr Perreau had come to have such a high blood alcohol level, Coroner McElrea was satisfied he was "grossly intoxicated" and that impaired his ability as a swimmer.
He made no formal recommendations, instead referring to Water Safety New Zealand's message: "Alcohol and water don't mix."
This was another case where the facts "speak for themselves," Coroner McElrea said.
• Making it harder to stay afloat due to lower concentrations of blood going to the brain and muscles contributing to heat and fluid loss
• Sharply reducing the ability to hold your breath
• Suppressing airway protection reflexes
• Making it easier to inhale water
Source: Water Safety New Zealand