An airliner in Taiwan with more than 250 passengers on board was forced to return to the airport soon after take-off because one of its doors was not shut properly, forcing the airline to apologise.

Taiwan's China Airlines (CAL) flight CI008 was at about 1,000 feet on December 9 when a warning signal indicated the problem, CAL spokesman Bruce Chen said.

The Boeing 747-400 carrying 264 passengers returned to Taoyuan International Airport after spending 40 minutes over the ocean to release fuel to make a safer landing.

It was unclear whether the door was not fully sealed before take-off or it loosened in the air, as a pre-departure check showed the aircraft's function to be normal, Mr Chen told reporters.

"We want to say sorry to the passengers onboard the flight. We are still investigating the cause of the matter and we will ask the Boeing company to explain," he said.

The local Apple Daily News cited an unnamed flight attendant as saying that some frightened passengers were crying when they heard the sound of wind coming through the door.

The paper said the aircraft took off again after a three-hour inspection.

In August, a China Airlines Boeing 737-800 exploded in a fireball shortly after landing in the southern Japanese island of Okinawa while all 165 passengers and crew fled to safety with just minutes to spare.

It was the latest setback for China Airlines, which has reported nine fatal accidents since 1970.