Five men were rescued from the Waikato River tonight after the dinghy they were using to get from Fieldays capsized.
At least one of the men, found clinging onto the edge of the boat, was minutes away from being sucked under water, police said.
Their boat had become tangled in underwater debris near the Narrows bridge and capsized, forcing the men to cling to it for 40 minutes while it floated towards Hamilton city.
The men were spotted as they called for help, and a passer-by called 111.
None of the men were wearing life-jackets and they had been drinking alcohol before their journey, police said.
All of the men were suffering from hypothermia, and were treated by paramedics when they were back on dry land.
One of the men had become separated from the boat and was rescued by a waka crew training on the river.
Three others were rescued by the police river rescue boat, deployed about 6pm, and the fifth man managed to get to the shore near Melville.
"These were mature men who could have taken steps to be safer on this occasion,’’ Sergeant Pete van de Wetering of Hamilton police said.
"It is questionable as to whether the boat was of adequate size to carry five men, especially with the current high river level and the fact it is running faster than normal due to this week's storm."
One or more of the men could have died in the accident, Van de Wetering said.