Canadian rescuers have recovered three more bodies after a Spanish fishing boat sank off Canada's east coast overnight, bringing the death toll to 10.

"Regrettably, JRCC Hfx can confirm that an additional 3 deceased individuals have been recovered from the sunken fishing vessel," tweeted the Joint Rescue Coordination Centre in Halifax on Tuesday.

Eleven people are still missing, and three sailors have been rescued out of the 24 people on board the boat.

There were 24 crew members onboard the vessel when it went down some 250 nautical miles east of Newfoundland, with rescuers still searching for the remaining 11 crew despite difficult weather conditions, officials said.

Spain's Transport Ministry identified the crew members as 16 Spanish nationals, five Peruvians and three Ghanaians.

The Villa de Pitanxo, a 50-metre fishing vessel which is based at a port in Galicia, sent out two distress calls which were received at 5:24 am (0424 GMT) in Madrid, the ministry said.

'Weather is challenging search'

Five hours later, another Spanish fishing vessel that was in the area spotted two life rafts, one of which was carrying three survivors and several bodies, it said.

Rescuers later found another four bodies.

"In one, there were just three survivors who were in a state of hypothermic shock because the temperature of the water is horrible, very low," Maica Larriba, a representative of Spain's central government in the Galicia region, told public radio.

She said the survivors had been airlifted to safety by a Canadian coastguard helicopter and that rescuers had found two other life rafts that were "totally empty" while searching for a third.

Canadian rescuers said they were hopeful more survivors could be found.

Canadian rescuers had deployed a helicopter, a military plane, a coastguard ship and several boats to search for the missing crew members, officials said.

"The weather right now is challenging for the search. It's approximately four-metre waves and visibility is down to approximately one-quarter nautical mile," Brian Owens of Canada's Joint Rescue Coordination Centre (JRCC) told the AFP news agency.

It was not immediately clear what caused the boat to founder.