The Dunedin City Council has plans to buy a geological treasure trove in a bid to keep it safe from mining.
The Foulden Maar site near Middlemarch is a 23-million-year-old crater lake containing large deposits of diatomite and fossils.
Plaman Resources bought the land in 2014 with the intention to purchase a neighbouring property to mine and break down the diatomite for animal feed.
But that proposal caused significant controversy.
Plaman Resources went into receivership and liquidation in June with its liquidators planning to sell the land - which has a mining permit.
But the council has taken the first step towards bringing the land back into public ownership by issuing Notices of Desire under the Public Works Act 1981.
Dunedin Mayor Aaron Hawkins said Foulden Maar was considered by scientists to contain the country's richest trove of fossils and needed to be protected.
"We believe we will have public support for the council to purchase this land. Notwithstanding the significance of Foulden Maar, in July 2019 Save Foulden Maar Incorporated was established and approximately 11,000 people signed its petition to central and local government ministers urging the acquisition as a scientific reserve," Mr Hawkins said.
Under the Act, the council must obtain a valuation for the land and negotiate with the owner for at least three months.
If the council doesn't reach an agreement with the owner, it will be up to the full council to decide whether it wants to proceed to a compulsory purchase.
The council has one year to make that decision once the Notices of Desire is served.