One NZ's promising to "vigorously defend" itself in new court action, over claims its new Space X service will provide "100-percent coverage"

The Commerce Commission's filing criminal charges against the telco over the claims.

The competition watchdog says the coverage will be initially limited to texts, and may not be available inside buildings or cars, or under trees.

But One NZ says its new service will effectively end mobile black-spots.

It says its language is consistent with how the industry and the regulator describe coverage, and the legal action will have implications for the whole sector.