The way has been cleared for further drilling in the Maui natural gas field off the South Taranaki bight.
The Environmental Protection Agency (EPA) has given the all-clear for Shell Todd to use a hack-up rig near the existing Maui A and B platforms between 35-50km off the coast.
The consents were lodged in October last year. The company asked for EPA permission to place and later remove the drilling rig as part of its 2018-19 exploration programme.
A second consent covers potential discharge of harmful substances from drains on the rig deck during drilling but comes with conditions.
The decision was made by an EPA-appointed Decision-making Committee (DMC) chaired by Kerry Prendergast with Gerda Kuschel and Miria Pomare as members. All three members agreed to grant consent based on information from submissions and evidence provided in a process that included a public hearing in New Plymouth.
The committee found the potential effects of the proposed activities, including cumulative effects, would be temporary or involve small areas of marine habitat and could be managed by the conditions of consent.
EPA climate, land and oceans general manager Siobhan Quayle called the decision "robust" and said it had been made after a careful assessment of all evidence.
"The application contained a number of unknowns and uncertainties. This meant the DMC needed to seek further information on several occasions to have the best available information to make its decision," Ms Quayle said.
The DMC found that while the proposed conditions were generally appropriate, it made a number of changes to ensure the environmental effects of the application would be appropriately managed. It means Shell Todd cannot have more than one jack-up rig on the seabed in the Maui field at any one time. The jack-up rig can be installed and removed up to 12 times within the existing 500m exclusion zones around the Māui platforms. The rig can be installed and removed up to eight times at locations outside these exclusion zones.