Clean-up efforts following an oil spill in the Awakino River in the King Country will continue overnight.
Waikato Regional Council says about 20,000 litres of oil spilled after a tanker crash on State Highway 3 in Awakino Gorge, between Piopio and Mokau, on Wednesday.
The council says most of the oil that spilled appeared to have gone out to sea.
However, booms are being used at the Awakino boat ramp to trap the remaining oil and trucks with sucker hoses are removing it.
This extraction will continue through the night.
The council says an initial assessment shows no major environmental impacts around the river mouth or on the coast.