Five people have been reported dead after a boat capsized near Kaikōura on New Zealand’s South Island, in a potential collision with a whale.

The 8.5 metre long boat was carrying 11 people, a group of 10 bird enthusiasts and a skipper, in Goose Bay off the South Island’s coast.

Police divers recovered five bodies from inside the boat, while the remaining six people — including the boat’s skipper — were rescued and are now in a stable condition.

Kaikōura’s mayor Craig Mackle told RNZ he believed the boat had potentially capsized because of a whale. But police have yet to confirm what exactly the boat collided with and are still investigating the situation.

“We have an upturned boat tipped over by a whale from what we can understand, come up from underneath,” Mackle said.

A statement from New Zealand Police said: “We are still in the very early stages of piecing together what has occurred”.

“The exact circumstances surrounding the incident will be subject to an extensive investigation, which will involve multiple agencies.”

Mayor Mackle also gave some info to the Associated Press. He said sperm whales and humpback whales were currently in the area, and that the water was calm.

“It always plays on your mind that it could happen,” he said about the potential chance of a whale and a boat crashing.

Locals helped with the rescue efforts, though they had fears for people who had fallen overboard because of the cold water temperatures.

Maritime NZ confirmed two investigators will travel from Christchurch, but investigations will only happen after all the rescue and recovery operations are finished.

“Maritime NZ offers its heartfelt condolences to the family and loved ones of the people who have died in today’s incident,” said Maritime NZ Principal Investigator Tracy Phillips.

NZ Police are currently notifying next of kin.

Image: Getty Images / Kai Schwoerer / Stringer