A Chinese satellite has spotted an object floating in the southern Indian Ocean which could be from missing Malaysia Airlines flight MH370. Malaysia's transport minister Hishammuddin Hussein confirms the object is 22 metres long and 13 metres wide Reuters

A Chinese satellite has spotted debris in the southern Indian Ocean that could be related to Malaysia Airlines flight MH370, officials said on Saturday, in what is hoped to be a strong lead after two weeks of fruitless searching for the missing aircraft.

Satellite images, taken on 18 March, show an object measuring 22 metres by 13 metres (72ft by 43ft) floating 1,550 miles south-west of Perth, Australia. The suspected debris was spotted 75 miles south-west of another floating object – measuring 24 metres (79 ft) across – that was sighted two days earlier but not yet found.

It is unclear whether the objects are the same or unrelated. Rough weather in the southern corridor could move floating objects at high speed, and if the objects lose any air they could sink quickly. Australian officials had expected the 24-metre object to have moved closer to Perth rather than away from it.

Malaysia's defence and acting transport minister, Hishammuddin Hussein, confirmed the sighting during his daily news briefing in Kuala Lumpur, when he was handed a hand-written note saying that China would be investigating.

"The news that I just received is that the Chinese ambassador received a satellite image of floating objects in the southern corridor, and they will be sending ships to verify," he told journalists. The Chinese authorities were expected to make an announcement on Saturday night about the images.

Australia's prime minister, Tony Abbott, said a civilian plane had spotted "a number of small objects very close together within the Australian search zone". He said the debris included "as I understand it, a wooden pallet".

Nearly 30 nations are involved in the search for flight MH370, which left Kuala Lumpur for Beijing on 8 March and disappeared from radar screens roughly two hours after takeoff with 239 people on board. The last known satellite "ping" made by the plane has led investigators to look for the aircraft along two flight corridors stretching from the last known location in the Malacca Strait – one dipping south towards the Indian Ocean, and the other north towards Turkmenistan.

The search in the northern corridor has so far found nothing, with China, India, Pakistan, Burma, Cambodia and Kazakhstan reporting no sightings. Australia's Maritime Safety Authority is leading the search in the Indian Ocean, where six planes scoured 10,500 square nautical kilometres on Saturday, despite a cyclone warning throughout the southern corridor. Strong winds and rough seas have been forecast, posing potential problems for Chinese, British and Australian ships that have headed to the same area. Chinese, Australian and Japanese aircraft are expected to head searches from Sunday.

A Chinese satellite image of an object spotted in the southern Indian Ocean that could be wreckage from missing Malaysian Airlines flight MH370. Photograph: Reuters

Australia's deputy prime minister, Warren Truss, has cautioned that much of the debris sighting must rely on human endeavour. "While these aircraft are equipped with very advanced technology, much of this search is actually visual," he said, vowing that Australia would "do whatever we can" to help find the aircraft.

Malaysia has also requested assistance with deep-sea surveillance equipment to potentially help look for the plane and its black box in the southern corridor.

As authorities continue to investigate possible hijacking or terrorism motives behind the missing plane, a transcript of the conversation between MH370's pilots and Kuala Lumpur's air traffic control has been released.

The transcript indicates that everything on board MH370 was normal for the first 54 minutes of the flight, although Malaysia's civil aviation chief dismissed the report as "not accurate", without explaining why. Some analysts have pointed to the co-pilot's curious repetition of the aircraft's altitude at 1.07am – a crucial moment, at which point the plane's automatic communications system sent out its last signal. A final "All right, good night" was also transmitted to air traffic control after the system was disabled, it is believed.

The search for debris comes amid growing frustration among relatives of the missing, who feel let down by the authorities. In China, relatives were prevented by police from confronting Malaysian officials after a heated exchange, during which relatives called the Malaysian government "murderers" and demanded answers.

"Tell us the truth! Give us back our loved ones!" shouted a group at Beijing's Lido hotel, where airline representatives host the daily news briefings and some relatives have been holed up for the past two weeks.

"The Malaysian government is deceiving us. They don't dare to face us," said another relative. "The Malaysian government are the biggest murderers."

Nan Jinyan, 29, an engineer who is awaiting news on her missing sister-in-law, said she was increasingly frustrated with the airline's vague and often contradictory information regarding the missing plane. "If they can't offer something firm, they ought to just shut up," she said.

"I'm psychologically prepared for the worst and I know the chances of them coming back alive are extremely small. I never imagined a disaster like this would befall our family, but life has to continue."

• This article was amended on 24 March 2014. An earlier version of the photo caption said that the object spotted in the southern Indian Ocean is 22 metres long and 30, rather than 13, metres wide. The Malaysian transport minister was misheard.