Three Dead After Catamaran Capsized Off Newcastle

Police have confirmed three people died after a catamaran overturned north of Sydney, with several others being treated for hypothermia after being thrown into the freezing ocean.

About 10.10am an emergency beacon was activated from a catamaran that had overturned approximately seven nautical miles off the coast at Stockton Beach. Two rescue helicopters were dispatched to the scene, along with police and volunteer marine rescue boats.

Emergency services rescued two people -- a 45-year-old man and a 14-year-old girl. The two passengers were winched to safety and are being treated at John Hunter Hospital for hypothermia.

Sadly, three other people were found dead by emergency responders.

It is not yet known what caused the boat to capsize, but police said conditions in the ocean -- high seas and strong 30 knot winds (or 50km/h) -- were "messy".

The overturned catamaran. Photo: ABC

"Our information is the vessel left Shoal Bay this morning, heading south towards Ettalong," Detective Acting Superintendent Grant Healey, of NSW Police, said in an afternoon media update.

As of Thursday afternoon, the vessel is still overturned and weather conditions are preventing emergency services from recovering it.

"It is now capsized and drifting off Newcastle. It's not in a position where we can recover it yet or salvage it yet," Healey said.

"Warnings have been sent out to the marine community and the sailing community to avoid the hazard. When we get favourable weather conditions, attempts will be made to salvage the boat."

The overturned catamaran with a responding boat. Photo: ABC

Healey said police said they were unsure how long the people were in the water, but that it was "the cold season and it doesn't take long to get hypothermic." Authorities are now searching for the next of kin of all victims.

Police have praised the multi-agency response from volunteer and emergency staff.

An Ambulance NSW spokesperson told reporters that all passengers were wearing life jackets.

“Also what made the rescue quite difficult is being an overturned vessel, there was quite a lot of debris and ropes in the water at the time," he told reporters.

The catamaran capsized approximately seven nautical miles off the coast at Stockton Beach. IMAGE: Google Maps

It comes as the Bureau of Meteorology forecasts a cold front to continue to move through the state on Thursday, bringing vigorous westerly winds.

READ MORE: Charlie The Dog And His Owners Rescued From Burning Yacht

Fishers and boaties have been told to be extra cautious as strong westerly winds are forecast to batter the coastline.

Choppy conditions are expected on exposed bays as well as dangerously rough conditions offshore and there's a risk of boats dragging or breaking free from moorings.

The rescue operation continues.

More to come.