Managers at one of New Zealand's oldest and biggest gasfields go before a special hearing this morning to seek the right to keep on operating.
The Maui field was discovered off the Taranaki coast in 1963 and started producing in 1979.
At that stage it was one of the biggest gasfields in the world.
It has produced vast quantities of gas in the past three and a half decades but needs a marine consent to keep on operating under new legislation governing New Zealand's Exclusive Economic Zone.
An Environmental Protection Authority hearing, beginning today, will consider an application by Shell Todd Oil Services for a marine consent for 35 years.
This will govern not just the field and its two gas rigs but related facilities such as an underwater gas pipeline.
A decision is expected by June and the authority is thought likely to approve the application.
That is because a report written on behalf of the authority concluded that continuing to operate the gas field would not cause significant adverse effects on the environment or existing interests.
It said any potential adverse effects could be avoided, remedied or mitigated through conditions imposed on the marine consent, if it was granted.
Despite this, EPA staff insist the matter has not been pre-judged.
Shell Todd Oil Services will make its case, and other submitters include various Government agencies and local Government, as well as Taranaki Maori interests and a variety of environmental groups.
More than 20 groups or individuals will make verbal submissions.
After starting its hearing in Wellington, the case will move to New Plymouth.
It is not clear how the 35-year extension being sought fits in with the fact that Maui was written off as facing depletion ten years ago, but has had its life expectancy extended several times since then.