A pilot's been winched out of the water tonight, after ditching their plane in Tasman Bay, 42 kilometres north of Nelson

Maritime NZ received reports around 7.30pm, and two helicopters, multiple boats and a New Zealand Defence Force Poseidon aircraft joined the search.

The pilot was the only person on-board the light aircraft... and is now in Nelson Hospital.

Nelson Marlborough Rescue Helicopter Pilot Dion says the conditions were favourable for the rescue.

He says there was only 10 knots of wind and the sea was calm.