The Commerce Commission has laid charges against the company Vodafone for alleged breaches of the Fair Trading Act.
The commission says the charges relate to representations made by Vodafone in various broadband and mobile phone promotions since 2006.
The representations included the extent and coverage of its broadband wireless network and mobile phone network and its charges.
Vodafone says it is surprised by the action and has never tried to mislead customers.
The company likens the Commission's action to using a sledgehammer to crack a nut.
Companies found guilty of breaching provisions of the Fair Trading Act may be fined up to $200,000 for each charge.