NIAGARA FALLS, Ont. - The survivor of a 60-metre plunge over Niagara Falls that caught the attention of hundreds of onlookers was identified by police Thursday as a 30-year-old Ontario man who was suicidal.

Police believe the man deliberately jumped into the frigid, turbulent waters on Wednesday afternoon, spending at least 30 minutes in the Niagara River before being rescued.

"He voluntarily entered into the water and refused our assistance at the base of the falls," said Niagara Parks police Chief Douglas Kane.

The man, who was identified only as a resident of western Ontario, was recovering at Hamilton General Hospital after being treated for hypothermia and a head injury. His condition was upgraded Thursday from critical to stable.

"He's expected to fully recover within the next few days," Kane said.

Police did not release the man's name, nor would they discuss his reasons for allowing himself to be swept away.

The rescue took place in front of hundreds of people visiting Niagara Falls on a cool but sunny afternoon.

The man was first seen climbing over a retaining wall above the Horseshoe Falls. He then climbed down to the water's edge and jumped into the fast-moving water that carried him into the Niagara River below.

Police spotted him floating about 300 metres from the base of the falls and yelled at him to swim to shore, but he wouldn't listen.

A private helicopter then hovered above him, using the force from its rotor blades to create a current that pushed him toward shore.

Once he was close to shore, the rescuers pulled him out, naked and semi-conscious.

He is only the third person known to have survived going over Niagara Falls without protection.

The last was Kirk Jones in 2003.