A couple fled their luxury yacht early this morning when it was engulfed in flames and sunk in the Marlborough Sounds.

Fire communications shift manager Karl Patterson said fire services got the call just before 2am.

The 15m "Aqua Luna" was "well ablaze" off the shore of Bay of Many Coves when fire services arrived.

"The superstructure was totally destroyed and flames were coming out the vents at the waterline."


Picton fire volunteers responded on Coastguard boats with the help of the Picton Tug, which helped light the way, Mr Patterson said.

The couple on board escaped in an inflatable boat and were treated for smoke inhalation at Bay of Many Coves resort by ambulance staff.

The boat then drifted north into Chaucer Bay where it sank.

The fire was not being treated as suspicious, but it wasn't known how it started, he said.

The couple were not New Zealand nationals, Mr Patterson said.