The Coastguard says a salvage crew is getting ready to remove the small plane which crashed and sank in the Raglan Harbour in Waikato this afternoon.
A woman was critically injured in the crash, and her husband and brother, who was piloting the Piper Cherokee, escaped with minor and moderate injuries.
An eye witness said the plane was about 150 metres in the air when its engine cut out.
It hit the water and started sinking but the three occupants managed to escape and have now all been transported to Waikato Hospital.
Half a metre of the plane's tail was visible above the water, about 100 metres from shore.
The Coastguard's Wally Hawken said they had been stood down, and now the salvage crew would wait for the tide to go out and pull the plane in on foot.
Police said the beach was full of holiday makers so it was fortunate the plane avoided the high density area.