TWO TUG boats are plodding along the NSW coast to rescue a luxury superyacht and its crew who?ve been stranded at sea for more than 24 hours.

The boats have been making their way to the stricken vessel since being dispatched from Sydney on Tuesday morning but are not expected to reach the yacht until 7pm tonight, the maritime safety authority says.

The four crew members stuck on board spent a night in the dark after losing power when the yacht broke down just after 5am on Tuesday.

The 37-metre multi-million dollar yacht, Masteka 2, sent out a distress call when it lost steering and started taking on water about 260km from Port Macquarie on the mid-north coast.

A cruise ship in the area, Carnival Spirit, responded to the distress call and diverted its path, rescuing two female crew members and monitoring the ship before resuming its trip to New Caledonia, where it will drop off the women.

A Carnival Australia spokesman said both women rescued were in good health and would continue with the cruise ship to New Caledonia.

The other four crew chose to stay aboard to try to save the sinking vessel and were able to successfully plug the leak.

Two dewatering pumps were air-dropped to the yacht AMSA Dornier aircraft and the crew have been given supplies including satellite phones.


?The crew have said they managed to stop the leak and the pumps are keeping the water out,? the AMSA spokesman said.

?They?ve said they are confident they can stay afloat and they?ve organised for the tug boat to come from Sydney.?

The superyacht is regarded as one of the most impressive vessels available for charter in Sydney, with hourly hire rates starting at $3000 and 48-hour charters fetching $40,000.

An Australian Maritime Safety Authority spokesman said it was not clear exactly why the Masteka 2 lost its steering and started taking on water.

The tug boat support is expected to arrive on the scene this evening.

The AMSA spokesman said the Masteka 2 was effectively adrift until then, but relatively calm conditions meant it was under no immediate threat from the elements.

?They have the ability to deploy sea anchors as well, which turns them around into the swell,? he said.

Today?s rescue was the second time in 10 days that Carnival Australia ships had responded to emergencies at sea.

Last week the locally based Sun Princess rescued five family members of a senior Vanuatu Government minister after their vessel was adrift in the South Pacific for more than 48 hours.

Based in Sydney, the Masteka 2 is available for both holiday charters and corporate and private events.

With five bedrooms and levels of luxury enjoyed by the rich and famous, the superyacht comes with a hefty price tag ? even by the hour.

A short stay will set a party back at least $40,000 ? a minimum two-night stay at $20,000 a night ? while a week during high season costs $125,000.