Four members ratified the auction, against one - Prawit Leesatapornwongsa. Prawit asked for the log files, containing data from the auction rooms, before he would make a decision if there was collusion or not.
"I have been serving as a soldier for almost 20 years. I'm doing my best to serve the King. I will continue delivering my best until the end of term (at NBTC)," the telecom committee's chairman Settapong Malisuwan said before voting "yes" to the result.
NBTC commissioner Suthipol Taweechaikarn said during the broadcast that the reserve price was set below fair value, to allow competition by small operators.
"If rules bar competition from small operators, that'd would be collusion. But competition did exist. I'm deeply wounded, hearing all damaging news which create public confusion," he said.
NBTC has been criticised for raising only Bt41.625 billion from the auction, slightly 3 per cent above reserve prices.
After the voting, bid winners are required to pay half of bid prices to NBTC within 90 days. the 15-year licenses will be issued within 7 days after payment.
The voting took place as a civic group submitted a petition to Senate Speaker Nikom Wairatpanich, pressuring for the removal of all 11 commissioners of the National Broadcasting and Telecommunications Commission.
The petition was filed as NBTC's telecom committee is on live broadcast, to defend the Oct 16 auction.
Surasak Siriporn-adulsilp, a leader of the civic group, brought with him a paper containing 57,904 signatures.
The civic group alleged that the commissioners may have committed a malpractice, following the 3G auction on Oct 16.
They said the auction ran against the public prosecurement law and violated the code of ethics. The auction required huge cost and did not take into consideration maximum benefits of the public. The auction also violated the Articles 30, 37 and 47 of the Constitution.
Nikom told reporters that all the signatures would be verified and then the petition would be forwarded to the National Anti-Corruption Commission. The verification process may take more than 30 days, he said.
Should the NACC find substantial evidence to support the civic group's charges, the Senate will then push for the removal, he added.