The cleaning up of thousands of toxic waste sites has been pushed back for at least a decade after the government dropped it as a priority.
Two weeks ago, the government announced it was putting $4 million into cleaning up the contaminated Calwell Slipway in Nelson, which is rated as the country's fourth-worst site.
But it is just one of perhaps thousands of contaminated sites, and it is still not known how many there are.
Ministry for the Environment figures have shown that regional councils have identified almost 20,000 potentially contaminated sites across New Zealand, and many have not been investigated.
They include former timber mills, chemical plants, factories, mines and farms.
A contamination expert from Massey University, Chris Anderson, said there were tens of thousands of sheep dip sites contaminated with arsenic and chemicals like organo-chlorines, but no-one remembered where they all were.
The Green Party said that was not good enough.
It secured a Memorandum of Understanding with the National-led government in 2008, which led to regional councils having to draw up lists of all their contaminated sites.
They were directed to clean up or manage all high-risk sites by the end of 2015 - last year.
But the ministry confirmed it had pushed out the deadline for clean-ups to 2030.
Green Party spokeswoman Catherine Delahunty said that was hugely disappointing.
Ms Delahunty said most sites were not being cleaned up because there was no public pressure, and no government interest.
"People don't want to their land or the land near them to be associated with a toxic site because it might affect property values," she said.
"We have to stop pretending these sites don't exist because we have not had the political will to clean them up."
Minister for the Environment Nick Smith said he did not apologise for that, because contamination was only a mid-ranking priority compared to climate change, air quality and freshwater.
Dr Smith said the government had to make choices, and the truth was it could get "far bigger bangs for its buck environmentally" in other areas like river clean-ups, home insulation and clean-air programmes.
He said his ambition was for New Zealand to quietly chunk its way through toxic sites one by one, doing a good clean-up job, instead of a quick job.
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