Traffic delays as oil slick being cleared on Great South Rd

Firefighters are cleaning up an oil slick at the intersection of Great South and Sylvia Park roads in Auckland. Photo / File

An oil slick on one of Auckland's busiest thoroughfares is causing cars to "slide all over the road".

Northern fire communications shift manager Scott Osmond said it was unclear how big the oil slick was at the intersection of Great South and Sylvia Park roads but firefighters were cleaning it up.

Police have been called in to help with traffic management.

A witness said the slick was "causing cars to slide all over the road".