China says one of its military aircraft has spotted three objects floating in an area where the search for missing a Malaysia Airlines jet is focused.

A Chinese aircraft has spotted three objects floating in an area off the West Australian coast where search teams are focusing their hunt for the missing Malaysia Airlines plane.

The development came on Saturday as an Australian Navy frigate was dispatched to join the operation, which is now focused on a new search zone more than 1000km from where teams had previously been scouring the Indian Ocean.

China’s state news agency Xinhua reported on Saturday that the Chinese military plane, Ilyushin IL-76, had spotted three floating objects of white, red and orange colours respectively, from an altitude of 300 metres.

Satellites and aircraft have spotted numerous floating objects, but none have been confirmed as wreckage from the plane.

Planes and ships on Saturday combed the newly targeted area with Prime Minister Tony Abbott saying authorities were transporting a black box locator to the search zone.

Flight 370 disappeared on March 8 after veering sharply off course while heading from Kuala Lumpur to Beijing with 239 passengers, including six Australians, and crew.

Investigators believed the Boeing 777 crashed in the southern Indian Ocean off the coast of Western Australia, where planes and ships have been looking for more than two weeks in the hope of recovering debris.

HMAS Toowoomba was due to leave a Perth naval base on Saturday afternoon and help with the search after being diverted from other operational tasks.

It will take with it a S-70B2 Seahawk helicopter.

Another Australian navy ship, the Ocean Shield, was due to leave Perth on Sunday to join the search.

The plane and its passengers have been missing for three weeks, but Malaysia’s transport minister has vowed to continue the search for “possible survivors.”

“No matter how remote the odds, we will pray, hope against hope, and continue to search for possible survivors,” Hishammuddin Hussein told reporters on Saturday during a condolence visit to relatives of Malaysian passengers and crew.

Malaysia says the plane was deliberately diverted from its planned flight path, and investigations have focused on the captain.

Malaysian police, the US Central Intelligence Agency and Federal Bureau of Investigation, Chinese intelligence and Britain’s MI6 are involved in the investigation.

The search zone shifted 1100 kilometres on Friday following a fresh assessment of satellite data.

It’s about 80 per cent smaller than the previous search zone but still spans 319,000 square kilometres.

The Australian Maritime Safety Authority (AMSA) said ships were trying to recover objects first spotted on Friday, including two rectangular items that were blue and gray.

“The objects cannot be verified or discounted as being from MH370 until they are relocated and recovered by ships,” AMSA said in a statement.

“It is not known how much flotsam, such as from fishing activities, is ordinarily there. At least one distinctive fishing object has been identified.”

Weather was against the searchers on Saturday with a cold front bringing rain, low clouds and reduced visibility to the southern part of the search area, while moderate winds and swells of up to two meters were predicted by the Bureau of Meteorology.

Conditions are expected to improve by Sunday but rain, drizzle and low clouds are still likely.