Australia’s largest mobile operator Telstra will be barred from participating in an upcoming digital dividend spectrum auction because the country’s regulators are concerned a winning bid would increase the incumbent’s dominance.

The restriction issued by the Australian Communications and Media Authority (ACMA), which was supported by the coalition government, follows guidance from the Australian Competition and Consumer Commission that Telstra should be excluded from the auction, The Australian reported.

Telstra, with a 52 per cent share of the country’s mobile connections, owns more than 50 per cent of available low-band spectrum. Two-thirds of its 16 million users are on 4G plans.

With Telstra ruled out the likely contenders will be Vodafone, Optus and TPG Telecom. They will compete for two blocks of 15MHz spectrum in the auction, which is expected to raise as much as AUD1 billion ($752 million).

The government announced in October that 30MHz of 700MHz spectrum, left unsold in the digital dividend sale back in 2013, will be put up for sale.

The government set the reserve price at AUD1.25 ($0.93) per megahertz per capita covered, which is the same as the reserve price for the 2013 auction adjusted for a shorter licence term, The Australian said.

ACMA is expected to call for auction applications in January 2017.