These Four key areas are:

1. Production & Exploration
Around 75% of New Zealand's natural gas comes from the Maui field, offshore from Taranaki on the North Island's western coast. The remainder is from 10 other onshore fields in the same area. Pohokura field, offshore from northern Taranaki, will come online in 2006. Companies involved at this level include Shell and Todd, as well as Swift Energy, Indo-Pacific, Greymouth Petroleum and Preussag.

2. Transmission
After processing, natural gas is piped to many urban locations in the North Island on two transmission networks. One is operated by NGC. 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.

3. Distribution
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 largest gas distributor by connections. There are currently three other distribution companies: Gas/GasNet, Vector and NGC. In April 2003 the Ministry of Energy requested the Commerce Commission to consider specific controls on the supply of natural gas transmission and distribution services. The Commerce Commission is due to complete its inquiry by November 2004.

4. Retailing
There are currently seven companies engaged in gas retailing:

• Contact Energy
• E-gas
• Genesis Energy
• NGC
• Todd Energy/NovaGas
• Wanganui Gas
• Auckland Gas