Offshore seismic operators in New Zealand are considering a legal response against Prime Minister Jacinda Ardern's government in the wake of its abrupt decision last month to stop issuing new offshore exploration permits.

The geophysical companies are unhappy because they have in recent years spent considerable sums of money on the acquisition and processing of seismic data on a multi-client, or speculative, basis.

In some cases, the companies also invested in the reprocessing of seismic data.