Thailand’s second largest operator dtac has opted not to participate in the re-auction next month of the 900MHz spectrum forfeited by Jas Mobile.

The announcement by dtac chief executive Lars Norling does not come as a surprise as the operator has long said the reserve price should be set at the original reserve price and not at the price Jas Mobile won the spectrum.

He said dtac has sufficient spectrum to support efficient 4G services despite not winning a licence in last year’s 900MHz and 1.8GHz auctions. The operator uses 15MHz of 1.8GHz spectrum, under a concession with CAT Telecom, for 4G service and plans to use an additional 5MHz by June.

Norling urged the regulator to hold an auction for the 1.8GHz spectrum before the concession expires in 2018, the Bangkok Post reported. Dtac also has 15MHz in the 2.1GHz band, which it uses for 3G service.

Earlier this month the Thai government rejected an offer by market leader AIS to match Jas Mobile’s failed bid for the 10MHz block to avoid allegations of favouritism. AIS was the second highest bidder for the original 4G block and last month made an offer to pay THB75.65 billion ($2.1 billion) for the licence to avoid the need to hold a 4G spectrum re-auction.

The re-auction date is scheduled for 27 May.

The National Broadcasting and Telecommunications Commission’s draft rules had earlier barred True, which won spectrum in both the 900MHz and 1.8GHz bands last year, from participating, but the government ruled that all operators can join except for Jas Mobile.

True, the country’s third largest operator, has not made a decision on whether it will participate in the May auction.