Lagos, Johannesburg: Emirates Telecommunications Group Co is suing Nigeria competitor MTN Group Ltd. over plans by Africa’s biggest wireless company to buy local internet provider Visafone Communications Ltd.

The lawsuit centres on MTN’s potential use of Visafone’s 800 megahertz of spectrum, Abu Dhabi-based etisalat’s Nigeria unit said in an e-mailed statement on Monday. “Not to challenge will entrench the dominance of MTN in the data services market,” the company said.

MTN Nigeria has been served with court papers and the phone company was in court last week about the matter, spokesman Funso Aina said by text message.

Tony Ojobo, a spokesman for the Nigerian Communications Commission (NCC), the regulator that approved the Visafone deal, said the NCC hasn’t received any official correspondence from etisalat questioning the approval of the MTN acquisition.

In 2013, the NCC said MTN, the biggest mobile-phone company in Nigeria, had become dominant in the mobile-voice market. The South African company is also in talks with the regulator to settle a $3.9 billion (Dh14.32 billion) fine for missing a deadline to disconnect unregistered subscribers last year.

MTN had 62.5 million Nigerian subscribers as of the end of September, according to the NCC’s website. Globacom and Airtel Nigeria had about 31 million each, while etisalat was the country’s fourth-biggest operator with 23 million customers.

MTN shares declined 0.8 per cent to 140 rand as of 12:04 pm in Johannesburg, valuing the company at 259 billion rand ($16 billion).