Brazil’s telecoms regulator Anatel has banned three of the country’s biggest mobile operators from offering new contracts to customers as a penalty for poor network performance, reports The Financial Times (FT).

Telecom Italia’s Brazilian subsidiary TIM, Carlos Slim-owned Claro and local operator Oi will be banned from selling new services in selected states from Monday. Anatel said the move was taken due to a growing number of complaints about calls being cut off or interrupted.

TIM has been banned from selling new voice and data plans across 19 of the 27 Brazilian states including Rio de Janeiro and Brasilia. Claro is forbidden from offering new contracts in three states, including business hub Sao Paulo, while Oi has been similarly hit in five states. Any operator contravening the ban will be fined BRL200,000 (US$99,000) per day per state.

The three companies have been given 30 days to submit action plans about how they intend to improve their networks. Anatel will then assess whether these plans are sufficient for it to lift the contract bans.

Telefonica-owned Vivo, CTBC and Sercomtel have also been ordered to present action plans about how they can improve their services, but have not been subject to the same contract suspensions.

According to the FT, Anatel is under pressure to be firmer with the country’s privately-run operators about service levels as Brazil prepares to host the football World Cup in 2014 and the Olympic Games two years later.