SOFIA, Feb 3(Reuters) - Bulgaria's telecoms regulator will auction on March 15 three frequency licences that will allow the development of 5G wireless networks in the Balkan country, it said late on Tuesday.

The Communications Regulation Commission said it would auction three, 20-year licences in the 3.6 GHz spectrum, each with an initial price of 4 million levs ($2.5 million).

"The auctions will be for licences with a national coverage for the use of bands in 3,500-3,600 MHz, 3,600-3,700 MHz and 3,700-3,800 MHz," the regulator said in a statement.

Both leading telecom operator Vivacom and A1, part of Austria's A1 Group controlled by Mexico's America Movil , have expressed an interest in acquiring the three licences, each for 100 MHz, while Telenor Bulgaria, owned by Czech investment group PPF, wanted one licence.

Vivacom and A1 have been offering some 5G services since the autumn, based on temporary frequencies granted by the regulator. Telenor Bulgaria, which carried out 5G trials in 2019, is yet to reveal its 5G rollout plans.

With an estimated combined investment of over 800 million levs over the next few years, the three telecoms firms have asked for lower frequencies fees and less bureaucracy to push ahead with a swift 5G rollout.

The regulator granted additional temporary frequencies in the 2.6 GHz spectrum to the three companies earlier this month.

($1 = 1.6264 leva) (Reporting by Tsvetelia Tsolova. Editing by Mark Potter)