Shell Todd Oil Services has started a new phase of drilling at the country's oldest natural gas field in South Taranaki.
The company says drilling recently started to extend the life of the Kapuni field, which began commercially producing gas in 1969.
Two new wells are being drilled from the existing wellsite KA1/7 and the work is expected to take about 6 months.
Before that, another Kapuni well was worked-over, a process which involves drilling a new section to get missed pockets of gas.
Shell Todd says the controversial process of fracking is not being used but may be used later on.