A Roads and Maritime Service spokesperson said a single northbound lane was being intermittently closed to allow heavy equipment to move in.

Wollongong police said traffic had been diverted via the Old Princes Hwy at Bulli Tops after the truck rolled onto its side, spilling diesel fuel onto the road.

The Mercury understand’s the truck involved may have been carrying coal.

An earlier incident on Mt Ousley Rd, where a number of break downs and a fluid spill caused the closure of two northbound lanes, has now been cleared with lanes reopend.

For further traffic information visit www.livetraffic.com or call 132 701.