A Chinese military plane searching for signs of debris from Malaysia Airlines Flight 370 spotted several objects floating in the sea on Saturday, including two bearing colours of the missing jet.

But it was not immediately clear whether the objects were related to the three-week-old investigation, and the second day of searching in the area ended with no evidence found of the jet, officials said.

The Chinese Ilyushin IL-76 spotted three floating objects, China's official Xinhua news agency said, a day after several planes and ships combing the newly targeted area closer to Australia saw several other objects.

Ships from China and Australia scooped up items described only as "objects from the ocean", but none were confirmed to be related to Flight 370, said a statement from the Australian Maritime Safety Authority, which is overseeing the search.

Relatives and friends of the passengers said they were tortured by the uncertainty over the fate of their loved ones, as they wait for hard evidence that the plane crashed.

"This is the trauma of maybe he's dead, maybe he's not. Maybe he's still alive and we need to find him. Maybe he died within the first hour of the flight, and we don't know," Sarah Bajc, the American girlfriend of US passenger Philip Wood, said in Beijing.

"I mean, there's absolutely no way for me to reconcile that in my heart," she said.

The three objects spotted by the Chinese plane on Saturday were white, red and orange in colour, the Xinhua report said. The missing Boeing 777's exterior was red, white, blue and gray.

An Australian PC3 Orion search plane also sighted objects in a different part of the search area, but the maritime safety authority did not describe those objects in greater detail.

An image captured a day earlier by a New Zealand plane showed a white rectangular object floating in the sea, but it was not clear whether it was related to the missing jet or was just rubbish.

Flight 370 disappeared on the 8 March while bound from Kuala Lumpur to Beijing, and investigators have been puzzled over what happened on board the plane, with speculation ranging from equipment failure and a botched hijacking to terrorism or an act by one of the pilots.

The latter was fuelled by reports that the pilot's home flight simulator had files deleted from it, but the Malaysian defence minister, Hishammuddin Hussein, said checks, including one by the FBI, had turned up no new information.

"What I know is that there is nothing sinister from the simulators, but of course that will have to be confirmed by the chief of police," he said.

Newly analysed satellite data shifted the search zone on Friday, raising expectations that searchers may be closer to getting physical evidence that the plane crashed in the Indian Ocean with 239 people aboard.

That would also help narrow the hunt for the wreckage and the plane's black boxes, which could contain clues to what caused the plane to be so far off-course.

The US navy has already sent equipment that can detect pings from the back boxes, and the Australian prime minister, Tony Abbott, told reporters in Sydney that the equipment would be put on an Australian naval ship soon.

"It will be taken to the most prospective search area and if there is good reason to deploy it, it will be deployed," he said, without giving a time frame. Other officials have said it could take days for the ship – the Ocean Shield – to reach the search area.

The newly targeted zone is nearly 1,130km (700 miles) north-east of sites the searchers have crisscrossed for the past week. The redeployment came after analysts determined that the Boeing 777 may have been travelling faster than earlier estimates and would therefore have run out of fuel sooner.

The new search area is closer to Perth than the previous one, with a flying time of two-and-a-falf hours each way, allowing for five hours of search time, according to the Australian Maritime Safety Authority.

AMSA said five P3 Orions – three from Australia and one each from Japan and New Zealand – plus a Japanese coastguard jet, the Chinese Ilyushin IL-76, and one civilian jet acting as a communications relay took part on Saturday.

"The weather in the area was reasonably good – most of the area we were able to see four or five kilometres or more," Royal Australian Air Force Flight Leiutenant. Russell Adams said. "The sea state was up, however, which meant there were quite a few whitecaps in the area so the crew would have had a bit of difficulty discerning between objects in the water and the whitecaps, so it made it hard for the guys today."

Some family members in Beijing said they want to fly to Kuala Lumpur to seek more answers from the government, but an airline representative said it may have to wait a day because of a lack of hotel space this weekend because of the Formula One Malaysian Grand Prix race on Sunday.

Steve Wang, a representative of some of the Chinese families in Beijing, said about 50 relatives wanted to go to Malaysia because they were not happy with the responses given by Malaysian government representatives in China.

"Because they sent a so-called high-level group to meet us, but they have not been able to answer all our questions," he said. "It's either they are not in charge of a certain aspect of work or that it's still being investigated, or it's not convenient for them to comment."

Malaysia Airlines' commercial director, Hugh Dunleavy, said on Saturday in Beijing that the airline was trying to facilitate the relatives' travel to Kuala Lumpur, but that plans had not been confirmed because of the difficulties in booking hotels this weekend.

If investigators can determine that the plane went down in the newly targeted zone – which spans about 319,000 sq km (123,000 square miles) – recovery of its flight data and cockpit voice recorders could be complicated.

Much of the sea floor in the area is about 2,000 metres (6,600 feet) below the surface, but depths may reach a maximum of about 6,000 metres (19,700 feet) at its easternmost edge.

The hunt for the plane focused first on the Gulf of Thailand, along the plane's planned path. But when radar data showed it had veered sharply west, the search moved to the Andaman Sea, off the western coast of Malaysia, before pivoting to the southern Indian Ocean, south-west of Australia.