A boatload of fishermen are lucky to be alive tonight after they were thrown overboard near Kawau Island and swept away in rough 2m waves and high winds.

NZ Coastguard Kawau skipper Luke McCarthy says his staff are "ecstatic" with the result of the dangerous rescue after receiving an SOS call from a fishing boat shortly after 11am today.

The group of five fishermen had earlier anchored off Kawau Island in the Hauraki Gulf about 45km north of Auckland when the 6m vessel began taking on water.

Within seconds the boat began listing and capsized - throwing the men into the sea.

The vessel's captain managed to stay with the capsized boat as the four others were carried away.