In January Britain's Serious Fraud Office announced that Rolls Royce had paid out huge sums over three decades to win contracts in Indonesia, Thailand, India, Russia, Nigeria, China and Malaysia.
Rolls Royce admitted to wrongdoing and agreed to pay a USD 808 million fine to authorities in Britain to settle the case.
But the UK probe has sparked follow up investigations in some of the countries where the bribes were received.
Thailand's National Anti-Corruption Commission (NACC) on today said an initial fact-finding committee had uncovered "reasonable suspicion" of wrongdoing.
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The statement said the probe would centre on the "transport minister, their deputy, the THAI Airways board and Thai Airways' long-term investment subcommitee" between 2004 and 2005 over a deal to buy six passenger jets with Rolls-Royce engines.
The statement did not name any suspects.
At that time the government was headed by Thaksin Shinawatra, a democratically elected prime minister who was toppled in a military coup in 2006. Two transport ministers served during that period.
The Thai Airways board at that time contained major business figures as well as five senior Air Force officers and a police general.
Thai law places a statute of limitations on most crimes and some of the alleged offences that took place before Thaksin took office can no longer be prosecuted.
Civil compensation claims can still be made though it is not clear if authorities plan to do so.
Thai Airways launched its own investigation after the UK probe became public.
The current military junta that seized power in 2014 has vowed to root out corruption.
But critics say junta probes have selectively targeted political opponents while top brass have also found themselves accused of graft.
Others say the military's push has had some effect, especially on cutting out the expected "tea money" needed to secure large government contracts.
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