The National Broadcasting and Telecommunications Commission (NBTC) will send a second warning letter to TrueVisions next Monday ordering the pay TV operator to comply with the channel-numbering rule immediately.
If the operator still does not rearrange its numbers for the first 36 channels, it will face a penalty and pay at least a 20,000-baht fine per day.
TrueVisions is the only major cable TV operator to shun the new channel-numbering system.
The broadcasting committee yesterday held a meeting on the issue and resolved to try one more time before penalising TrueVisions.
NBTC secretary-general Takorn Tantasith said he assigned NBTC staff to follow up on the case and verbally warn TrueVisions to comply with the rule.
If TrueVisions insists on ignoring the rule this time, its licence will face suspension and ultimately revocation if it fails to comply.
The daily fine could range from 20,000 to 5 million baht.
TrueVisions executives declined to comment on the issue.
Mr Takorn wants TrueVisions to weigh the public interest against the company's own benefit when considering channel numbering.
Since Dec 2, every TV platform across digital, satellite and cable has been required to have the same numbers for the first 36 channels.
Meanwhile, the court case between TrueVisions and the NBTC is still pending with the Central Administrative Court. The court dismissed a request for an emergency injunction to rearrange the line-up of the first 36 channels.
The pay TV operator said the change would confuse its subscribers.
Before Dec 2, platform operators were allowed freely to arrange their first 10 channels.