Ruapehu District deputy mayor says the town of Raetihi could have its water supply shut off for up to two weeks after a major diesel leak on the Turoa skifield.
Work has begun on decontaminating the Makotuku stream in the Tongariro National Park after 15,000 litres of the fuel spilled from a tank at the base of Turoa ski field on the weekend of 29/30 September.
The diesel seeped into Makotuku Stream which feeds the Raetihi town water supply. Ruapehu District Council shut off the supply on Wednesday.
Deputy mayor Don Cameron says booms are being used in the stream to capture diesel and remove it, but the terrain is steep and the decontamination could take some time.
Mr Cameron says the water will be restored to Raetihi either when the stream is completely clean of diesel, or an alternative water source is accessed.
Man confirmed ill from contaminated water
One person has become sick after drinking the contaminated water.
There had been early reports that two people may have become ill, and a local surgery was monitoring patients with stomach complaints to determine whether the problem was viral or related to drinking contaminated water.
Mr Cameron says one man who drank quite a lot of the contaminated water is ill, but is recovering well.
The Manawatu/Wanganui regional council has said contaminated topsoil will be removed from the area of the leak and water cannons will be used to flush the stream.
The council said with rain forecast for next week, the diesel would make its way downstream too quickly to capture, and a controlled flush will ensure teams can harvest as much residue as possible.
Meanwhile, a Department of Conservation team was on Saturday searching the stream's catchment for any native whio (blue ducks) affected by the spill.