Small blobs of oil washed up on beaches north of Wellington on Monday are believed to be from a crude oil spill off Taranaki a month ago.
Greater Wellington Regional council says the globules have been found at the high-tide mark between Mana and Otaki on the Kapiti Coast.
The council suspects the oil has come from a 1000-litre leak from production ship Raroa.
Regional harbourmaster Mike Pryce warns people not to walk along the high-tide mark or let their dogs wander there.