Siswanto, a relative of Sugianto Lo and Vinny Chynthya Tio who were aboard the ill-fated aircraft with five other Indonesian nationals, said the accuracy of Najibs statement remained doubtful due to the absence of strong evidence, such as the planes wreckage.
Therefore, as quoted by Medan-based Waspada Online on Tuesday, Siswanto urged the Malaysian Airlines authority not to tell the passengers relatives in a hurry if the evidence remained unavailable.
An uncle of Firman Chandra Siregar, a passenger of the missing Boeing 777-200 ER passenger jet, also doubted the Malaysian governments statement on the aircrafts final fate.
"We hope Chandra is alive because we watched on television that some credible persons have opined that the aircraft is likely safe," Chandras uncle Firman R. Siregar said, as quoted by the Kompas daily on Tuesday.
Besides Lo Sugianto, Chynthia Vinny and Firman Chandra Siregar, four other Indonesians aboard the aircraft are Ferry Indra Suadaya, Herry Indra Suadaya, Indra Suria Tanurisam and Willy Surijanto Wang.
Indonesian President Susilo Bambang Yudhoyono had previously expressed his deep condolences to the Malaysian government and people as well as the families who lost their loved ones in the MH370 tragedy.
"My deep condolences are to their families and my prayers are with those on MH370. May the soul of their loved ones rest in peace," President Yudhoyono said in a statement on his official twitter.
In a short statement in Kuala Lumpur on Monday night, Malaysian Prime Minister Najib Razak confirmed that the jetliner that went missing for 17 days had crashed into the Indian Ocean and killed 239 people on board.
Najib cited the groundbreaking satellite-data analysis of the British company Inmarsat to ensure the crash of the ill-fated aircraft that lost radar contact while flying from Kuala Lumpur to Beijing, China, on early March 8.
According to the Malaysia Airlines authority, those on board the ill-fated aircraft consisted of 153 people, including one infant, from China/Taiwan, 38 from Malaysia, seven from Indonesia, five from India, six from Australia, four from France, three including an infant from the United States, two from New Zealand, two from Ukraine, two from Canada, and one each from Russia, Italy, Netherlands, and Austria.
However, the Austrian and Italian authorities had denied that their citizens were on board the MAS flight MH370. Instead, they confirmed that their respective citizens passports had been stolen when visiting Thailand.
Malaysia was assisted by a number of countries to search for the missing plane, such as Indonesia, China, the United States, Australia and Japan.
Indonesia deployed five naval ships, a rescue helicopter and the Indonesian Air Forces maritime surveillance aircraft to help search for the missing plane.