A dispute over responsibility for 8500 tonnes of toxic waste in Southland is heading to court.
The Environmental Defence Society is this morning seeking a ruling from the Environment Court over who has ultimate responsibility for removing the ouvea premix from Mataura's disused papermill.
A byproduct of the aluminium smelter at Tiwai Point, it releases deadly ammonia gas when mixed with water.
The waste has been threatened by flooding and fire this year, sparking fears among locals.
The Environmental Defence Society has said Rio Tinto - as the smelter's owner - should have responsibility for cleaning it up in a timely manner.
New Zealand Aluminium Smelters contracted Taha Asia Pacific to deal with the waste products of Tiwai Point's aluminium production.
Taha moved more than 10,000 tonnes of ouvea premix and other dross into the papermill without resource consent six years ago.
The company subsequently went into liquidation still owing a $2 million bond to the Gore District Council for a retroactive consent for the dross.
The society's executive director, Gary Taylor, told Nine to Noon yesterday he wanted it gone before the end of the year.
"All of the parties involved - the Crown, the district council and the company - agreed to a funding formula by which the material would be removed from that site over time," Taylor said.
"That was a good start. The problem with it is that it's over time and we believe that material needs to be removed forthwith and certainly before Christmas."
New Zealand Aluminium Smelters and Rio Tinto have regularly reaffirmed their March 2018 commitment to the $4 million plan alongside local authorities and the government to move the waste from Mataura and other sites around Southland over six years.
Taylor said today's mediation marked the start of a legal process to determine if there was a practical way to get the dross out of Mataura faster.
"Not only is it a risk to public health but I'm very concerned too about the continuing community anxiety about it. It's a stressful time anyway in New Zealand without this on top of everything for the people in Mataura," Taylor said.
Local councils and the Ministry for the Environment will also join today's mediation.