"It is undeniable that the disclosure of such vital information is painfully belated, more than seven excruciating days after the 227 passengers and 12 crew memberslost contact with their beloved relatives and friends," state-run Xinhua said in a commentary.
The remarks came after Malaysian Prime Minister Najib Razak yesterday said that the communications systems of Flight MH370 had been deliberately disabled before the plane turned back and flew for seven hours in a different direction.
China is facing public outrage as 154 of 227 passengers aboard the missing Boeing 777 are Chinese nationals.
"Due to the absence - or at least lack - of timely authoritative information, massive efforts have been squandered, and numerous rumours have been spawned, repeatedly racking the nerves of the awaiting families," the hard-hitting commentary said.
China pressed eight ships, three aircraft and several helicopters for seven days to search for the Beijing-bound plane, which mysteriously vanished from radar screen an hour after taking off from Kuala Lumpur on March 8.
Winding up its search operations in South China Sea, Beijing is now diverting its fleet to Malacca Strait and Andaman Sea where plane was confirmed to have flown by new satellite data.
Besides Malaysia, the commentary also targeted the US.
"Given today's technology, the delay smacks of either dereliction of duty or reluctance to share information in a full and timely manner. That would be intolerable," it said.
"As the leader of the international search and rescue mission, Malaysia bears inescapable responsibility. Other parties that possess valuable data and information, including plane maker Boeing, engine manufacturer Rolls-Royce and intelligence superpower the US, should also have done a better job," the commentary said.
"With time ticking away and the fate of Flight MH370 still shrouded in mystery, it is vital and imperative that the Malaysian side work more thoroughly and efficiently and other major information holders -- not least the US -- be more open and forthcoming," it said.
After Najib's statement, Chinese foreign ministry called the Malaysian Ambassador here and asked Kuala Lumpur to share exact information.
A statement by the Foreign Ministry spokesman Qin Gang asked Malaysia to continue providing more "thorough and correct information" about the plane and sent its specialists to join the probe.
"Chinese technical specialists are on the way to Malaysia to help the investigation."