The one-year extension - the third that Todd has received from New Zealand's Crown Minerals - was granted just two days after the company made its application last Wednesday.

The original exploration licence had been due to expire at the end of this month.

Managing director Richard Tweedie told PetroleumNews.net the extension was granted because the Ministry of Economic Development unit wanted to do more work analysing the development project proposed by Todd over a year ago.

Todd had applied for petroleum mining permit PMP 38162 after it and Canadian company TCPL Resources found that delivering Karewa gas into a waiting carrier as compressed natural gas (CNG), taking it to shore and feeding into the North Island high-pressure system was a viable development option.

"Karewa is sort of like Kupe, it will be the last cab off the rank. Its day will inevitably come, as with Kupe, but gas prices will have to increase markedly," Tweedie told PNN from Wellington.

He declined to say by how much wholesale gas prices, currently about $NZ5.50-6.50 ($A4.41-5.22) per gigajoule, would need to increase to make the Karewa development economic, "but the increases would need to be significant".

Tweedie also said Karewa should be developed before any decisions were made about importing liquefied natural gas, referring to New Zealand's largest gas users, Contact Energy and Genesis Energy, and their plans to import LNG should explorers fail to find enough domestic gas over the next few years.