Texan oil giant Anadarko says it offered to give full oil spill modelling reports to the environmental regulator tasked with clearing its Taranaki Basin drilling plans, but was told that would not be necessary.

The company and the Environmental Protection Agency (EPA) are opposing an urgent legal challenge by Greenpeace, which alleges the EPA's decision to grant Anadarko permission to drill in the basin did not follow the procedures set out by law.

A judicial review hearing was held in the High Court at Wellington today, less than two weeks after Anadarko started exploratory drilling about 185km off the coast of Raglan.

Greenpeace alleges the EPA gave the company the green light to drill without seeing all the relevant information on its environmental impacts.


It said eight specific documents were not submitted to the EPA before it allowed drilling - including an emergency oil spill response plan, a well control emergency response plan, and oil spill modelling reports. But Anadarko's lawyer Mike Colson said the company had been open and transparent in its environmental impact assessment application to the EPA.

At a meeting in September, the company offered to give the EPA copies of oil spill modelling reports, which were among some 800 pages of documents referred to but not included in the company's application.

The full documents had been submitted to Maritime New Zealand, which was the agency responsible for cleaning up major oil spills.

However, the EPA said it did not need to see them, Mr Colson said.

"It was said that that wasn't considered necessary."

Mr Colson said Greenpeace's delay in filing the judicial review, which it did on the day drilling began, was deliberate.

He urged Justice Alan MacKenzie not to order "disproportionate" relief, such as ordering the EPA to reconsider Anadarko's application, should he find in Greenpeace's favour.

Anadarko had already invested $US190 million ($NZ228m) in drilling and would lose $US1.2m ($NZ1.44m) a day should its permission to drill be revoked.

Its drilling permit lasted only until next May, and delays could also impact Anadarko's plans to explore off the Canterbury coast this summer.

Earlier, Greenpeace lawyer Isaac Hikaka said the EPA had erred in the law during the consultation process because it had not considered a full impact assessment of the drilling.

The EPA rejected this today, and told the court the documents it had received from Anadarko had been sufficient.

EPA lawyer Paul Radich said the additional documents which Greenpeace allege were needed were not required. Those documents were considered by Maritime New Zealand.

Justice MacKenzie noted the need for urgency and reserved his decision.