The oil washing up on Manawatu beaches is unlikely to spread further north into the Rangitikei coastline.
A clean-up led by Horizons Regional Council has been under way since Monday afternoon after the discovery of oil washing up on a 10km stretch of coastline from Foxton Beach to 500m north of Himitangi.
It is still not known where the oil came from.
Council on-scene commander Ian Lowe said the response team had checked as far as Tangimoana but no new oil had hit the coast.
"Samples will be sent to a laboratory to help determine their source, which is still unknown. However, the focus is very much on the clean-up at this stage," he said.