Canterbury hunter Terry Austin, 53, resorted to rationing food after a flooded river near Lake Coleridge trapped his path to safety.

Down to a chocolate bar and a bottle of water, a Canterbury hunter admits things got desperate when a flooded river blocked his path home for three days.

Terry Austin went into the hills behind Lake Coleridge on Saturday, August 1, and was expected home the following Tuesday at the latest.

Hungry and tired with a worried son at home, Thursday dawned before he attempted risky river crossings to eventually hitchhike to safety and halt preparations for a search and rescue effort.

A swollen river blocked Terry Austin's path home for three days.

"I was [desperate], that's why I decided to make all an effort to get down the valley because at a point I've got to make a decision, I can't stay here forever."

It was not the first time the 53-year-old has been faced with adversity. He and three others were seriously injured in a helicopter crash near Taupo in 1997.

Austin rode a quad bike into the hills to meet with two hunters, who left the area the following day. He planned to stay longer alone but wet weather forced him to pack his bags on Sunday night for an early exit on Monday.

"I walked down the valley to my quad bike and the Harper River was flooded. Usually it's like a trickle. I reckon it came up close to a metre, it came up over the banks. There were trees floating down the river."

With the steep, bluff-like banks, any hope of escaping on Tuesday vanished as Austin watched the river continue to rise through rain and snow.

He made a radio call from a hut to the Department of Conservation, asking them to tell his 19-year-old son he was stranded. He had a personal locator beacon if the situation became dire.

Austin considered a six to seven hour trek on an alternative route leading to the State Highway 73 but with dwindling food stocks and poor weather conditions, he decided to stay patient.

A break in the weather came on Wednesday but the river was still in flood, so Austin rationed his remaining food – three Moro bars, a dehydrated food packet, two puddings, tea bags and milk powder.

He decided to make an exit attempt early Thursday, discovering the river had dropped but "still not quite enough". He got two thirds of the way on his submerged quad bike before the river flow because too strong.

"I managed to shimmy down the side of the river to reach Glenthorne Station on the other side of the river.

"I went round hills and upstreams, got to a shingle road called Harper Rd, and then I hitched a ride. I survived the Thursday on one Moro bar and a drink bottle. I was starving."

He waved down a vehicle from Glenthorne Stationwhich took him to safety hours before police planned to begin a search effort for him.