Tearful relatives of those on board missing Malaysia Airlines flight 370 said Tuesday their torment has been awakened anew by the AirAsia loss in Indonesia, nine months into their nightmare.

"It is just like what happened nine months ago when I heard the news of MH370," said Steven Wang, whose 57-year-old mother was on the flight which remains one of the biggest aviation mysteries ever.

"I can feel the desperation that the next-of-kin are suffering now. It is terrible. It is horrible," he said.

Wang emerged as one of the most vociferous campaigners for answers on how MH370 went missing on March 8, one hour into a flight from Kuala Lumpur to Beijing.

An unofficial leader of hundreds of Chinese relatives who packed into often rowdy meetings with airline officials in the weeks after the disappearance, Wang was a sombre shadow of his former self after months of anguish.

"Most of the time now we are asking for information, but they say they have nothing," he said, with a dejected, weary tone.

Two-thirds of the 239 people on board the missing Boeing 777 are Chinese citizens.

A vast multi-national search has failed to find any sign of wreckage of MH370.

On Tuesday authorities looking for AirAsia flight QZ8501 -- also owned by a Malaysian airline -- said they had found bodies, the shadow of a plane and debris in the sea off Indonesia.

Selamat Omar, whose son Mohamad Khairul Amri Selamat was on MH370, said the news on AirAsia would provide some solace to victims' families.

"It looks like there could be no survivors after the QZ8501 crashed into the sea. I praise the Indonesian authorities and neighbouring countries for finding the plane in less than 50 hours after the plane vanished," he said.

"Now the victims' families can console themselves and give the victims a proper burial. The families can now have a closure and have a peace of mind which I am dying for."

For other families of MH370, coping with their personal nightmare has filled the days since the plane vanished.

"Our entire life is a mess now," said Xu Jinghong, whose 65-year-old mother Liu Fengying was one of 153 Chinese passengers who failed to return home.

"I lost 10 kilogrammes (22 pounds) in weight, I couldn't sleep well and don't dare to see photos of my mother or think about her," she added, her voice cracking with emotion.

- 'Flood of emotion' -

The disappearance of QZ8501 off Indonesia on Sunday sparked deep personal reflection on the plight of the relatives of the 162 people on board.

"I empathise with them because I've been there too," Xu said softly. "I want to tell them to take care of themselves."

Xu spoke to AFP from her Beijing home as she welcomed another MH370 relative Dai Shuqin, whose younger sister Dai Shulin was on the plane, along with three generations of her family.

Dai has channelled her grief into seeking answers from both Malaysia Airlines and the Chinese government over what happened to the jet.

She regularly visits a "support centre" which was set up near Beijing airport after Malaysia Airlines stopped paying for families to attend meetings at the Lido Hotel in the city.

"I still have hope -- always -- as long as there's no evidence to show that they are dead," said Dai, explaining why she continues her seemingly futile wait for answers.

"I won't give up," the 61-year-old added in determined tones, but in a sentence interrupted by tears.

"I have experienced so much pain and hardship, and I have worked so hard for answers."

American Sarah Bajc, whose partner Philip Wood was on MH370, told of the horror she felt learning another jet had vanished, a moment she said to herself: "Oh my God -- it has happened again."

Bajc and Wood previously lived in Beijing, but were planning a life together in Kuala Lumpur before the plane's disappearance.

Speaking from the Malaysian capital, she likened her emotions on hearing about MH370 with the loss of both the AirAsia jet and MH17, another Malaysia Airlines fight that went down in strife-torn eastern Ukraine in July with 298 people on board.

"You just instantly start to shake because all that flood of emotion of what we went through on March 8 all comes back," she said.

"You can't even control it. It's impossible. It is just a physical response."

"Then you start thinking what those poor families are going through and you think 'Oh my God' -- nobody has to go through that."