SUBANG JAYA/BEIJING - Distraught relatives of passengers on missing Malaysia Airlines flight MH370 on Friday called for Malaysia to withdraw its declaration that all onboard had died in an accident.

About 20 - mostly Malaysian but with some from China and the United States - gathered in Subang Jaya despite a downpour to tell reporters that "almost all families are unanimous in our stand that we do not want to declare our loved ones dead, without a shred of evidence".

"I wanna know what happened. I'd rather not have conversations about compensation," said American teacher Ms Sarah Bajc, whose boyfriend Mr Philip Wood was on the flight that disappeared en route to Beijing from Kuala Lumpur on March 8 last year.

Malaysia's Department of Civil Aviation announced on Thursday that after 327 days and over S$130 million spent searching for the Boeing 777 in the treacherous southern Indian Ocean, the 239 on board had to be presumed dead.

It said that the decision had been made with the agreement of China, which had 153 citizens on the plane, and Australia which is currently leading the search off its west coast.

However, despite rejecting the verdict, Ms Jacqinta Gomes, whose husband Patrick was inflight supervisor, admitted that some families needed the compensation in order to survive. "At the present moment we haven't decided anything yet," she said when asked about possible legal action to overturn the yesterday's declaration.

According to Ms Bajc, about 10 to 20 per cent of families had engaged lawyers and were trying to put together a legal strategy.

The relatives had also crowdfunded over US$100,000 (S$125,030) to hire an international investigation firm in September last year, she said, which had found nothing so far as records were "suspiciously" clean.

"It's like going to a house where you think there's a murder... but it's been stripped clean of any sign of life," Ms Bajc said.

Voice370, a group of next-of-kin of some of the 50 Malaysians on board MH370, said in a press statement on Friday: "We have stated it before and reiterate it again, that we are prepared for any eventuality, including the fact that our loved ones may never come back.

"However, almost all families are unanimous in our stand that we do not want to declare our loved ones dead, without a shred of evidence!!"

In Beijing, more than 100 Chinese relatives of the lost passengers are requesting Malaysia take back their statement, according to posts in an online group they use, Agence France-Presse reported.

"We call on Malaysia to withdraw their statement. It lacks a basis in evidence," said Mr Jiang Hui, whose mother was on the plane, calling on authorities to apologise.

"They gave up searching for survivors after 40 days."

Family members, some of whom burst into tears as they spoke to reporters near a Buddhist temple in Beijing, said they had received little advance warning of the announcement, reported AFP.

"Malaysia ignored the right of relatives to know the news first," Mr Jiang added.

Furious accusations from Chinese relatives that Malaysia had covered-up information about the loss of the flight during the 10-month investigation drew Beijing into the fray, straining bilateral ties.

Malaysia's official declaration that MH370 was an "accident" opens the door for compensation payments - but several relatives who spoke to AFP said they were not interested in compensation without further investigations.

"We don't want money. We want the truth about what happened," said Ms Hu Xiufang, whose only child, daughter-in-law and grandson were on the plane.

Chinese media reported on Friday that the father of an MH370 passenger died suddenly at his home just three hours after hearing the plane was missing.

Mr Li Xiaohui, 60, whose son was onboard, had no known serious medical problems at the time of his death, a state-run outlet called The Paper reported.

The relatives in China have formed a loose-knit group to express their demands, but China is wary of any unofficial organisations and they have met with harassment from police.

Around a dozen policemen on Friday surrounded relatives of MH370 passengers outside the temple, telling them not to speak to reporters and ordering journalists to leave the scene.

"The police stop us from speaking out, and threaten us," added Mdm Dai Shuqin, whose younger sister was on the plane, AFP reported. "They bully us, that's what Chinese police are like."

ADDITIONAL REPORTING BY AFP