KUALA LUMPUR (AFP) - National self-interest and confusion about operational control looked to be unsettling the already daunting 26-nation search for a missing Malaysia Airlines jet, with boats and planes sitting idle pending clear orders.

Malaysia has underlined the importance of outside help in scouring two land and sea corridors equivalent in size to the entire land mass of Australia.

But Indonesia acknowledged on Wednesday it had only just provided clearance for surveillance aircraft from Australia, Japan, the United States and Malaysia to overfly its territory, while saying its own vessels await instructions from Kuala Lumpur.

"It is not that Indonesia does not want to issue permits, but we have a mechanism to follow that we have to respect," military spokesman Iskandar Sitompul said, insisting Jakarta was not trying to "slow down" the process.

"It must go through the foreign ministry first before being submitted to the armed forces," he said.

MH370 went missing early on March 8 with 239 passengers and crew, spawning a massive international search across Southeast Asia and the Indian Ocean.

The hunt has turned up no trace of wreckage as the clock ticks down on the 30 days that the aircraft's black box transmits a signal.

The Thai air force revealed on Wednesday that its military radar had picked up what appeared to be Flight MH370 on March 8, just minutes after investigators believe it was deliberately diverted from its intended flight path by someone on board.

Although the aircraft ID could not be 100 per cent verified, the Thai data represents crucial corroborative evidence for the conclusions drawn from Malaysian radar tracking of MH370.

But it went unreported by the Thai military for nine days after the plane disappeared and only emerged following a check of radar logs on Monday.

According to Air Marshal Monthon Suchookornat, the same plane was picked up again later swinging north and disappearing over the Andaman Sea.

Nothing was done before because the aircraft was not in Thai airspace "and it was not a threat to Thailand," Monthon said.

Malaysia has sought help from more than two dozen countries in the form of radar and satellite analysis, as well as surveillance vessels and aircraft.

Acknowledging the "diplomatic, technical and logistical challenges" inherent in running such a multi-national task force, Acting Transport Minister Hishammuddin Hussein said on Tuesday that Malaysia was ceding some operational control.

Mr Hishammuddin said Australia and Indonesia had agreed to take the lead in the southern corridor across the Indian Ocean, with China and Kazakhstan doing the same in the northern corridor, stretching from northern Thailand into South and Central Asia.

But many of the countries involved are not used to such close cooperation - especially when it comes to sharing possibly sensitive radar data.

Many countries in the region, and beyond, have offered and provided technical and logistical support, but bureaucracy and lingering confusion appear to be delaying their operational deployment.

Indonesia said it was facing delays in deploying its own resources as it waits for a green light from Malaysia.

"Five navy warships temporarily halted their search of the Malacca Straits on Monday, as we await further information from Malaysia or elsewhere," Sitompul said.

India has similarly suspended search operations in the Andaman Sea for several days.

"No instructions received. ANC (Andaman and Nicobar Command) on standby awaiting further instructions," a navy spokesman said.

"It is not for us to take a call on this. It is between governments. We have to simply follow instructions. We are awaiting orders," said a source in the Indian defence ministry in New Delhi.

Paul Yap, an aviation lecturer at Temasek Polytechnic in Singapore, expressed sympathy for the Malaysian authorities, saying it was always going to be tough to steer so many countries in one direction.

"Right now, I think it is out of Malaysia's hands," Mr Yap said.

"They crucially need the partners involved to play ball... but I won't be surprised if some are not doing that. It is all about self-interest.

"For radar data, no country is going to reveal information that will show the shortcomings of their capability," he said.

"So I wouldn't like to be in Malaysia's shoes."

The investigation into the fate of the Boeing 777 has focused on findings it was likely deliberately diverted from its flight path to Beijing, probably by someone in the cockpit with advanced aviation skills.

But the drip-feed of often conflicting information from Malaysia has sparked fury among desperate relatives and condemnation from Chinese authorities. Two-thirds of those on board were Chinese.