''We have demanded that we meet with the prime minister and the transportation minister,'' Wang Chunjiang, whose younger brother was on the plane, said.

''We have questions that we would like to ask them in person.''

One representative of the families' organising committee, who wanted to be identified only by his surname, Jiang, said 35 family members arrived in Kuala Lumpur on Sunday morning, with more from Beijing to follow. He said Malaysia Airlines arranged for the family members to fly to Kuala Lumpur at their request.

''We want evidence, we want the truth, and we want our relatives,'' Mr Jiang, whose mother was on board the plane, said. ''In Beijing, we aren't getting any information.''

The Boeing 777 disappeared on March 8 with 239 on board, including 153 Chinese and six Australians.

The Malaysian government has come under strong criticism from China. Its government and state-run media helped to fan negative sentiment and suspicion against the Malaysian-led investigation. Relatives of the missing have accused the government of ''delays and deception'', and tensions remain high after families clashed with police as they tried to storm the Malaysian embassy in Beijing on Tuesday.

A smaller, peaceful protest was staged on Saturday outside the Lido Hotel in Beijing, where families have been staying for the past three weeks, and where daily information updates have been held by Malaysian officials.

Another family representative, Steve Wang, said relatives would not go to Perth unless conclusive physical evidence of the plane's wreckage was recovered.

Meanwhile, Malaysia will introduce stricter security checks following a stoush with Interpol over its screening of airline passengers. But they will not come into force until June.

Home Minister Ahmad Zahid Hamidi was reported on Sunday saying the new system would be introduced at Kuala Lumpur's international airport first.

His comments come as authorities said the FBI had so far found ''nothing sinister'' after examining the flight simulator that the captain of the missing Malaysia Airlines passenger jet kept in his home.

The high-tech simulator of Captain Zaharie Ahmad Shah has been the subject of intense interest by investigators amid speculation the 53-year-old aviation veteran may have been responsible for the shutdown of communications and dramatic change of course of flight MH370.

Spy agencies MI6 as well as the CIA are also helping the Malaysian authorities, which has added to speculation the aircraft was hijacked by terrorists.

A senior police source involved in the investigation said on Sunday: ''We have found nothing to indicate the pilot or co-pilot went wild.

''The FBI has found nothing. Everything is open, of course, but this is not a major issue for us any more.''