Auckland-based Greymouth Petroleum has filed claims in the High Court against the New Zealand government challenging the latter's decisions including no longer issuing new offshore exploration permits.

Greymouth said it regretted having to take court action but it had been unable to resolve differences with the country's Minister of Energy, Megan Woods, and government officials.

One of Greymouth's claims is that the government's 12 April 2018 decision to halt the offering of new offshore oil and gas blocks was unlawful.