Oil and gas company OMV has started pumping oil from a previously undrained section of the Maari field off Taranaki.
The production capacity is estimated to be at 4.5 thousand barrels a day.
Oil is being produced from a well known as MR8A, which was side-tracked from an abandoned injection well and drilled horizontally into the Moki formation to a length of 3,824 metres.
OMV said it was a great achievement to revitalise an existing field in the Tasman Sea, where it said conditions were challenging and remote; it is in 100 metres of water about 80 kilometres off the coast.
The development is part of OMV's Maari Growth project, which aims to increase reserves, production and recovery from the field.
The campaign is the start of a total of five wells that are expected to be drilled by mid next year.
OMV is the operator of the Maari Joint Venture, and holds a 69 percent stake.
The next largest partner is Todd Energy, which has a 16 percent share.
