Softbank President, Masayoshi Son, told a press conference that the allocation was decided in an unfair, closed-door manner and invited suspicion that the two companies have received favorable treatment because they have accepted former ministry officials for top posts.

The company’s opinion was backed by the third largest operator Vodafone KK, which called upon the ministry to give equal access on the frequency.

Son said he was prepared to sue the ministry if it refused to reconsider the decision.

Softbank has been planning an aggressive move into the market and aims to cut mobile phone rates by a double-digit percentage, a move that would cause consternation amongst existing operators.

In May, Softbank paid $3 billion for Japan Telecom Holdings Co. Ltd., the country’s third-largest fixed-line operator. If it can establish a mobile operation, it will be able to offer customers a bundle of internet access, fixed and mobile service and make an all-out assault on NTT Corp.