New Zealand Oil & Gas says that estimates of reserves in the Kupe oil and gas field - in which it has a stake - have increased 13%.
NZOG owns 15% of Kupe and says the field's operator has completed an assessment of the offshore Taranaki field.
Estimates of gas and LPG reserves rose, while those for light oil edged down slightly.
New Zealand Oil & Gas says it's now evaluating how it might speed up production of the additional gas.
