Greenpeace has opened its case against the Environmental Protection Agency and Texan oil giant Anadarko in the High Court at Wellington.
The organisation alleges the Environmental Protection Agency (EPA) failed in its role to properly consider whether permission should have been granted to Anadarko to drill for oil in the Taranaki Basin.
Anadarko, which began drilling about 185km off the coast of Raglan about two weeks ago, are second respondents in the case.
Today's case is the beginning of a judicial review sought by Greenpeace into the process in which the EPA granted the company permission to undertake oil drilling.
During his opening today, Greenpeace lawyer Isaac Hikaka submitted key documents and sections of reports stating possible impacts and emergency response plans to a possible oil spill were not considered by the EPA before it granted Anadarko permission to drill.