Man crushed by whale on NSW south coast

An 18-year-old man from NSW is fighting for his life in a coma after he was crushed by a whale in a freak accident on the state's south coast.

Friends Nick and Matt were fishing in waters off Narooma on Sunday when the whale surfaced and landed on their boat.

Both men were injured and the boat was taking on water, but 39-year-old Matt managed to navigate back to a boat ramp.

Nick, 18, was rushed to hospital with a broken neck and severe head injuries. He remains in a coma at Canberra Hospital.

Matt escaped with a concussion and cuts to his head.

Family friend Carmen Bartley said the pair had no warning and no idea the whale was nearby.

"At this stage, we don't know when he will wake up, or how this has affected his brain," Ms Bartley said in an GoFundMe appeal for donations to help cover Nick's medical expenses.

Police on Tuesday issued an appeal for boaties to be alert, with whale migration season bringing scores of the animals to NSW waters.

"While inquiries are in their infancy, the incident demonstrates the dangers these mammals can pose to those on the water," Marine Area Commander Superintendent Joe McNulty said.

"Given the close proximity to the shoreline, there is potential for some spectacular whale watching, but we encourage anyone hoping to get a closer look to maintain a safe distance"