The country's most toxic site will get a $3 million cleanup by the Government.
The soil around the closed Prohibition and Alexander mines near Reefton has some of the highest levels of arsenic in the world, while water near the mines is 33,000 times the safe limit for drinking water.
The sites also have high levels of mercury and cyanide.
In 2013, the Government said $28m was committed to cleaning up the country's contaminated sites, and estimated the cost of cleaning up the Prohibition and Alexander mines would be $600,000.
Environment Minister Nick Smith said the Government's plan to clean the site involved removing the contaminated soil and building a water treatment plant nearby .
It would be funded by the Ministry for the Environment and the Department of Conservation.