The companies running the Maui gasfield off the Taranaki coast have revealed there is still plenty of gas to be pumped out.
The Maui field has been producing gas since 1979, and its demise has been predicted several times.
But counsel for Shell Todd Oil Services Rachel Devine told the Environmental Protection Authority that the resource was far from dead yet.
"While the Maui field has come off its peak it is still a major gas producer," she said.
"In 2013 it produced 20 percent of New Zealand's total gas supply and held 18 percent of its remaining gas in reserves."
When Maui was discovered, it was one of the biggest in the world at the time, and Shell Todd Oil Services want the right to run it for another 35 years.
The consortium needs approval for this under legislation governing New Zealand's Exclusive Economic Zone, which was passed in 2012.
In pushing this claim, Rachel Devine told the authority the area which was being drilled was not environmentally significant.
"This is not a particularly sensitive or ecologically sensitive environment," she said.
"The seabed biological communities in the area are broadly representative of the wider South Taranaki bight. No threatened or endangered species were found in the benthic surveys of the area."
Ms Devine conceded there would be some impact from the operation, but the EEZ legislation did not prohibit this.
If Parliament wanted to ensure absolute protection for the environment she said it could have written this in to the legislation, but it did not do this.
And she went on to limit the claims that Maori could make, saying established customary fishing rights could be considered by the Authority, but applications for customary rights could not.
Not could a Waitangi Tribunal ruling granting Maori a treaty interest in petroleum resources.
That was because the law protected established interests, not potential ones.
"Applications for a protected customary right or customary marine title do not satisfy the definition of existing interests and that the Wai 796 claim to the Waitangi Tribunal and the Waitangi Tibunal's findings on that claim are not a settlement and do not satisfy the claim of existing interests."
Shell Todd Oil Services were dominating the hearings today and tomorrow but opponents of the application will have their say next week.
Meanwhile, about half a dozen protesters unveiled an anti-drilling banner outside the hearing today.
As well as a banner, the protesters placed a mock drilling rig outside the hearing but were ordered to remove it.