Analysis - New Zealand First, led by Parliament's longest serving MP, is playing the long game - both in building party support and policy.

New Zealand First will invest in surveying the country's offshore basins for oil and gas supplies to use domestically and export around the world, if elected.

Analysis - New Zealand First, led by Parliament's longest serving MP, is playing the long game - both in building party support and policy.

New Zealand First's oil and gas exploration policy is "a very high-risk way to spend $1 billion", a resources law expert says.