As with the electricity market, the gas market is similar in having four key areas.
1. Production and exploration
New Zealand’s natural gas comes from production sites in the Taranaki basin on the North Island's west coast. Of the six major gas fields in the area, Maui continues to produce approximately 33% of total gas production while the relatively new Pohokura offshore field produces almost 43%. Companies involved at this level include Shell, Todd Energy, OMV, and Greymouth Gas.
After processing, natural gas is piped to many urban locations in the North Island on two transmission networks. One is operated by Vector. The other, the Maui open access transmission line, is operated by a consortium owned by a number of parties including Shell, Todd and OMV.
Natural gas is not reticulated in the South Island.
The distribution companies deliver natural gas through pipes from the transmission gate stations to households and commercial and industrial end-users. Powerco is New Zealand's second largest gas distributor by connections. There are two other distribution companies in New Zealand - GasNet and Vector.
There are nine companies engaged in gas retailing: Contact Energy; Genesis Energy; Energy Online; Nova Gas; Mercury Energy; On Gas; Greymouth Petroleum; Energy Direct NZ; TrustPower.