New Zealand's oil and condensate reserves jumped 53 percent last year, buoyed by the development of the nation's offshore Tui oilfield and completion of Royal Dutch Shell's Pohokura project.

Remaining reserves in the country's producing oilfields rose to 148.3 million barrels at January 1 from 97.1 million barrels a year earlier, according to the Ministry of Economic Development. Gas reserves climbed 10 percent to 2.03 trillion cubic feet (0.62 trillion cubic meters), the ministry said Wednesday in an annual review.

Exploration has surged in New Zealand over the past three years as a shortage of natural gas prompted the government to open its gas and oil-bearing basins to international companies. A record 42 wells were drilled last year and oil is now the nation's third-largest export earner after dairy and meat products, Bloomberg News said.

New Zealand used about 31.5 million barrels of oil last year. It produced 14.9 million barrels of oil in 2007, the most since 1998, and about 170 billion cubic feet of gas.

The producing field reserve estimates exclude gas and oil held in projects being planned or in development. Including Origin Energy's NZ$1-billion (US$761 million) Kupe gas project and OMV AG's offshore Maari oil project, oil reserves rose 12 percent to 217 million barrels and gas reserves 17 percent to 2.41 trillion cubic feet.

The Tui field started production a year ago and was the nation's first offshore oil development since 1996.