Thailand's finance ministry on Friday called for a corruption investigation into the country's auction of third-generation (3G) mobile telephone operating licences because of fears of collusion.
All three companies that participated in Tuesday's sale secured three blocks of bandwidth each, according to the National Broadcasting Telecommunication Commission (NBTC), the telecom regulator.
"There was no real price competition," finance ministry deputy permanent secretary Supa Piyajitti wrote in a letter to the NBTC and the National Anti-Corruption Commission urging a probe.
"The spectrum is a limited resource so if there is inappropriate allocation or collusion it may result in a severe loss for the state and NBTC members may be held responsible under the law," Supa said, according to the memo released by her office.
She said there should have been fewer licences than bidders and a higher reserve price.
Leading telecom firms Advanced Info Service, Total Access Communication (Dtac) and True Move all secured licences in the sale, which critics tried to block because of fears of a lack of competition in the bidding.
Two firms bid the minimum reserve price and one offered only eight percent more in an auction that raised a total of 41.6 billion baht ($1.4 billion).
A business dispute meant that as other nations move to introduce faster 4G technology, Thailand has yet to roll out a proper 3G service, more than a decade after it was first launched in Japan.
Explore further: FX says overnight ratings becoming meaningless