Thailand’s telecoms regulator has given dtac, the country’s third largest mobile operator, the green light to use its 1.8GHz spectrum, currently deployed for 2G, to expand its 4G services.

Dtac runs 4G on the 2.1GHz band and has 1.3 million 4G connections, or about 5 per cent of its total use base, according to GSMA Intelligence.

The approval by the National Broadcasting and Telecommunications Commission (NBTC) comes with the condition that the upgrade to 4G can’t interfere with state-owned CAT Telecom’s plan to transfer 5MHz of 25MHz unused spectrum in the band to the NBTC for the upcoming auction, The Nation reported.

Dtac operates its 2G network on the 1.8GHz band via a build-transfer-operate concession with CAT.

The 4G auctions, which have been delayed by more than a year since the military coup in May 2014, will include the sale of 25MHz or 30MHz in the 1.8GHz band in November and 20MHz of 900MHz spectrum (two blocks) in December.

After months of pushing for more spectrum to be included, the NBTC said earlier in the month that the additional 5MHz of 1.8GHz airwaves would not be available in time for the auction because the return requires changes in the concession, which would take several months to complete.

But the country’s Deputy Prime Minister Prajin Juntong is opposed to moving ahead with only 25MHz and is pushing for the return of the 5MHz in time for auction on 11 November, the Bangkok Post said. Prajin held talks with the ICT minister yesterday to work out a way for the spectrum to be returned in time.

At least five companies have expressed interest in the 1.8GHz auctions: AIS, two subsidiaries of dtac, True Move and Jas Mobile Broadband, a subsidiary of Jasmine International.