The National Broadcasting and Telecommunications Commission (NBTC) may amend some strict conditions of its master plan governing frequency management in order to address the approaching expiration of two mobile service concessions.
The move is aimed at clearing existing legal deadlocks between relevant regulations and telecommunications laws, said Suthipol Thaweechaikarn, a member of the NBTC's telecom committee.
Concessions of True Move and Advanced Info Service's Digital Phone Co (DPC) on the 1800-megahertz frequency are due to expire next September.
The two companies use 12.5 MHz of bandwidth each.
Under the existing master plan, operators must immediately return frequency to the NBTC after concessions expire.
"Amending the master plan will allow operators to return their frequencies gradually at an appropriate time," said Mr Suthipol.
He said the telecommunications committee will submit the amendment proposal for board approval.
Section 84 of the Frequency Allocation Act of 2010 allows the NBTC to determine the time period during which operators must return spectra.
But the master plan, which took effect in mid-2012, says concessionaires must immediately return frequencies to the NBTC once their concessions expire.
The telecom watchdog will then auction off those frequencies.
Mr Suthipol said the two regulations are inconsistent.
If the NBTC follows the master plan strictly, then True Move and DPC will have to return their spectra immediately after September, and there will be a question as to who will serve the companies' existing mobile customers.
Mr Suthipol said that as a regulator, the NBTC cannot hire private firms to operate mobile service, or else they would risk a legal challenge.
"Tweaking the master plan would be the best choice for us to avoid any future legal backlash," he said.
Earlier, the NBTC said it might sell off the 1800-MHz frequency this coming April.