Oil company Apache says it has a 20 per cent chance of finding oil in commercial quantities in Hawkes Bay.
Apache has entered into a joint venture with Tag Oil, which has extensive exploration permits onshore in the East Coast Basin.
Apache has agreed to spend $100 million to explore and appraise the potential development programme in return for a share of any profits.
The work is planned to take place over the next four years with seismic surveying already under way.
Apache senior project adviser Alex Ferguson said the company had received permission from most land owners and local iwi consulted.