A government research boat is surveying the seabed off the Otago coast in preparation for increased oil and gas exploration.
The two week project by National Institute of Water and Atmospheric Research vessel Tangaroa will map 25,000 square kilometres of underwater landscape to to depths of five kilometres.
NIWA research manager Rob Murdoch says detailed maps of the seabed to 200 kilometres from the Otago coast are needed because of the growing interest in petroleum exploration.
Dr Murdoch says the Tangaroa's instruments will be able to record tsunami risks, determine animal habitats and detect gas plumes.
Oil companies Shell and Anadarko, which are exploring the southern petroleum basins mainly for gas, say the NIWA maps will be useful, especially for future environmental assessments.
The Oil Free Dunedin group says if they are so useful to the petroleum industry, it should be paying, not the cash-strapped taxpayer.