The vast majority of natural gas in New Zealand is bought and sold via bilateral contracts, the details of which are not publicly available. MBIE publishes quarterly energy pricing data, which includes natural gas.
A small amount of gas (around 4% in 2020) is traded on emsTradepoint, so more detailed pricing information is available, however these prices are not necessarily reflective of the market as a whole.
Original Link: https://www.gasindustry.co.nz/about-the-industry/gas-industry-information-portal/gas-pricing/
Page last saved: 3 June, 2021