Papua New Guinea - Ships and helicopters are continuing to search for more than 100 people missing after a ferry sank off Papua New Guinea's north coast on Thursday.

Almost 250 people rescued in a joint Australian-PNG operation have reached the eastern PNG town of Lae, officials said on Friday.

The search for the missing - mostly university students - resumed at daylight.

An official said there were fears people had been trapped in the ferry.

The MV Rabaul Queen, a vessel owned by PNG-based Rabaul Shipping, sank east of Lae some 10 miles (16km) from shore. The company said in a statement that there were 350 passengers and 12 crew onboard.

"We acknowledge that this has caused tremendous suffering. Our condolences go to the loved ones of those affected," said Rabaul Shipping managing director Peter Sharp.

Relatives of the passengers, angered by a lack of information, threw rocks at the company's office in Kimbe on Thursday, Australian media reported. Local police said it had to move the staff to an undisclosed location.

So far a total of 246 people have been plucked from the water. Most of the survivors who have returned to Lae were taken to the local hospital.

"None of them had sustained any real injuries.