UPDATED 2.30pm: Authorities are attempting to locate the owner of a boat that sunk in Tauranga Harbour this morning.

The 30ft launch was spotted taking on water by a member of the public from the end of 2nd Avenue, who alerted SunLive to the sinking.

The boat appears to be sitting on the bottom, according to a reporter at the scene. Photo: Andrew Campbell.

Neighbour Bruce Galloway noticed the boat was taking on water about 8.30-9pm last night, however calls to the regional council were unsuccessful.

All of the operators were busy, and after ten minutes Bruce phoned the Tauranga Coastguard, only for the call to go through to Auckland.

Georgie Smith at Coastguard Northern Region says after-hours calls are automatically patched through to Auckland.

There was no one on the boat, it was on a swing mooring and the situation was not life threatening to anyone.

'The situation involved property and as per our normal practice we tried to put him through to the harbourmaster,” says Georgie.

'We tried three different harbourmaster numbers and were unable to pass on the neighbour on the direct dial. We did not try and contact Tauranga coastguard.”

Bruce then called the harbourmaster's office this morning.

'At 7.30am this morning I phoned again, and made contact,” says Bruce.

At that time the water was just off the gunnels, he adds.

The boat, which is believed to have sunk at about 8am, is known to take on water and Bruce and his wife quite often hear the on board bilge pump working.

A neighbour has the owner's phone number, but the neighbour is away, and Bruce hasn't seen the owner visit his boat for a long time.

Deputy harbourmaster Chris Isherwood says a shoreline survey this morning hasn't found any sign of spilled fuel from the vessel. It's still attached to its swing mooring so it's not a navigation hazard.

The Harbourmasters' main concern is navigation safety, says Chris. As the boat is not a navigation hazard, its removal is the responsibility of the owner.

When contacted the owner will be given the numbers of contractors who will be able to raise the boat.