Operators of the gas pipeline from South Taranaki to Auckland are pressing on with attempts to sell it.
Global oil giant Shell has run the pipeline from the Maui gasfield under the ocean and across the upper North Island for 35 years.
It has two junior partners, the Todd corporation and Austrian company OMV.
It recently sold its service stations, which now form Z Energy, as part of a worldwide decision to focus instead on oil drilling and production.
The sale of the pipeline is part of that trend.
Shell quietly let the market know of its intentions last month but has made no public announcement on it.
The company said the pipe was originally built exclusively for the Māui natural gas field.
But an agreement was made in 2005 to open up access to the pipeline to other companies, and Shell said that meant it no longer needed to own the infrastructure.
At this stage, it was testing the market and was not saying what response there has been, it said.
The sale applies only to the onshore section of the pipe.
The Maui pipeline transports around 78 percent of all natural gas produced in New Zealand.
The sale comes as Vector makes a similar deal to offload its gas pipelines outside Auckland.
Vector will sell its gas pipes to global infrastructure asset manager First State Funds for close to a billion dollars.
