Whanganui District Council is selling its GasNet pipeline infrastructure in Papamoa to Australian company First Gas.
But the amount of the council windfall is yet to be revealed.
Last August, GasNet - which is owned by the council through its trading organisation Whanganui District Council Holding Limited - secured a deal to provide gas network infrastructure to several major new subdivisions in rapidly expanding Papamoa, just outside Tauranga.
Just before Christmas, the council signed papers to sell the Papamoa pipeline infrastructure as well as the agreements with the developers that went with it, and this month a settlement with First Gas was agreed.
Holding's chairman, Matthew Doyle, said the council had been offered an advantageous amount by First Gas and he believed the sale was a positive one for the district's ratepayers.
Mr Doyle said the money was in the bank, though the sale was still subject to the Commerce Commission for final approval.
Whanganui mayor Hamish McDouall said considering the competitive nature of the market it was good news.
"You often get big fish taking over small fish," Mr McDouall said.
"Considering it was a short-term investment and we got a 100 per cent return, I'd say we got a pretty good deal."
Mr Doyle said GasNet had planned for the Papamoa agreements to be a long-term investment.
"When we made the agreements with Papamoa developers it was not for a revenue gain but it was an opportunity for the future household owners to sign up with GasNet.
"It was a long-term game for a long-term gain. Developers are building around 400 houses, and sign-ups wouldn't have kicked in until the end of this year."
When GasNet made the agreements with the developers, Auckland gas company Vector owned the majority of the gas networks in Papamoa.
Since then, Vector has sold all its assets in Papamoa to First Gas.
Holding director Harvey Green said considering the ratio of GasNet's pipeline in Papamoa compared with the rest of GasNet, the First Gas offer was a really beneficial and positive one.
"In total, GasNet has about 370km of pipeline around New Zealand and our pipelines in Papamoa were only about 6km long," Mr Green said.
He and Mr Doyle confirmed that GasNet was not for sale and they were still looking to expand the company's network.
The company is the smallest gas operator in the North Island with between 3 per cent and 4 per cent of the market.