The Kupe gas project in Taranaki has been officially opened.
Prime Minister John Key opened the project, saying it helps with two of the Government's goals - boosting the country's energy self-sufficiency and exports.
Kupe is expected to provide about 15% of New Zealand's gas needs.
The $1.3 billion project is already up and running, producing natural gas from a well 30 kilometres offshore for electricity production at the Genesis power station in Huntly.
Kupe provides about half of domestic LPG demand, and tanker trucks are also shipping out light crude oil in the form of condensate, both for domestic use and export.