BEIJING - China's Foreign Ministry spokesman Hong Lei said on Saturday China had informed Malaysia and Australia its satellite had spotted a large object possibly linked to the missing flight MH370 soon after the sighting, state news agency Xinhua reported.

The object, around 22m long and 13m wide, was spotted in the southern Indian Ocean on March 18 by the high-definition earth observation satellite "Gaofen-1", China's State Administration of Science, Technology and Industry for National Defence (SASTIND) said on its website.

"China hopes that these data will be helpful for searching and rescuing efforts," said Mr Hong, who added that further analysis and verification are needed to ascertain whether the floating object was indeed part of the missing Malaysia Airlines plane.

The passenger jet, carrying 239 passengers and crew on board, lost contact with air traffic controllers during a red-eye flight from Kuala Lumpur to Beijing on March 8.

Mr Hong said that China's sea and air search-and-rescue forces are heading for the southern Indian Ocean where the satellite picked up imagery of the object at 44 degrees, 57 minutes south latitude, and 90 degrees, 13 minutes east longitude, at around 12am on March 18 Beijing time.

"China will continue to cooperate closely with parties concerned and share information with them, so as to make an all-out effort to search and rescue work," Mr Hong was quoted as saying by Xinhua.

The object was located around 120km south by west from two suspicious objects Australia had detected on March 16 but not yet found despite extensive search in the remote ocean off western Australia.

News of China's latest sighting broke dramatically when Malaysian Acting Transport Minister Hishammuddin Hussein showed a room packed with reporters and cameras a hand-scribbled note he had just received during his daily press briefing in Sepang earlier on Saturday.