The 700-megahertz licence auction will not take place in May as originally planned by the telecom regulator, as significant details of the auction terms have yet to emerge.
The regulator said bidders need time to prepare capital and bidding guarantees.
"The soonest timeline for the auction date may be August or September," said Takorn Tantasith, secretary-general of the National Broadcasting and Telecommunications Commission.
The NBTC insists that the planned auction of 700MHz licences is unaffected by the unsettled situation of the next government.
As an independent agency, the NBTC is proceeding with 5G auction procedures under its responsibility, regardless of politics, Mr Takorn said.
The drafts for the planned 700MHz auction were approved and public hearings held before the general election.
Mr Takorn said the draft for 700MHz spectrum recall, the compensation regime and auction conditions is expected to go into effect in April. Related conditions of the 700MHz auction, including reserve price for the range, will be finished by May, he said.
The NBTC needs at least three more months to complete related procedures for the auction, as well as a period for bidders to prepare bank guarantees for bids.
Digital TV operators now using the 700MHz range will be reassigned to 470-510MHz, freeing up the 700MHz band for 5G adoption in late 2020.
The 700MHz range contains 45MHz bandwidth of spectrum for upload and download (45x2). The NBTC plans to auction 35MHz divided into seven licences, each containing 5MHz of bandwidth.
Licence payments will be made for 10 years, and the licence validity is 20 years.
According to a study by Thammasat University in 2016, using the 700MHz band for 5G will generate direct benefits to the overall economy of 248 billion baht.
Previously, the NBTC subcommittee working on the 700MHz recall draft and compensation regime said it was unreasonable to hold the auction in May while lacking technical details such as network rearrangement and a clear compensation rate offered to digital TV and broadcast network providers.
The private sector and digital TV operators have voiced support for holding the bid in December instead of May.