The broadcasting regulator's plan to postpone digital TV licence fee payments for another year may not take effect.
Anti-graft groups are keeping an eye on the move, saying it favours private companies.
The National Anti-Corruption Commission (NACC) and the Office of the Auditor General (OAG) are closely monitoring the case after receiving complaints.
They said the postponement of digital TV licence fee payments, which are due on May 24, would affect the government's revenue collection.
This round of payments would be the second by 24 digital TV operators since receiving their licences from the National Broadcasting and Telecommunications Commission (NBTC).
Most of the complaints have come from people who said the payment delay was "inappropriate" and rooted in the unhealthy financial status of some digital TV operators, an NACC source said.
Meanwhile, a report by media researcher Nielsen Thailand said advertising spending on 24 digital TV channels stood at 8.7 billion baht in the first quarter, accounting for 26% of total ad spending in all media outlets.
The NACC source quoted the complaints as saying the delay in digital TV network expansion should not be used as a reason to postpone licence fee payment.
The source said the NBTC should solve the network delay problems by imposing a penalty on network providers.
Last month, the NBTC approved in principle the postponement of digital TV licence fee payments for 12 months.
Since the rise of digital TV, operators have been hit by domestic political unrest, the economic slowdown and a delay in digital TV network expansion and subsidy coupon distribution.
A public hearing on the payment delay was held last week. Most of the 24 digital operators agreed to put off the second licence fee payment worth a combined 8.1 billion baht.
But they did not agree with the charge of a 7.5% interest rate, as it would not serve to ease their financial burden.
Operators wishing to make their second payment on May 24 can still do so.
Sombat Leelapata, the NBTC's acting deputy secretary-general, said the broadcasting panel would clarify the issue with three government agencies — the NACC, the OAG and the Office of the Attorney General — to ward off potential lawsuits.
The postponement process must be clarified before the second payment comes due on May 24.
"It looks like we're in a dilemma," Mr Sombat said.
"If we do postpone the payment of digital TV licence fees, we may face an investigation by the NACC. But if the postponement does not occur, digital TV operators may take legal action against us."