More than 100 firefighters are still dousing a fuel tanker with foam after the truck burst into flames on the side of a motorway near Wollongong.
The truck was carrying 36,000 litres of fuel along the M1 Princes Motorway west of Wollongong when it caught fire before 9am on Friday.
About 20 emergency crews are on the scene spraying the flaming vehicle with foam, a Fire and Rescue NSW spokeswoman told AAP.
The 44-year-old male driver, the only occupant of the truck, was able to escape unharmed.
Crews battled to keep the blaze within containment lines as the fireball repeatedly flared up with fuel spilling onto the roadway and into drains.
Firefighters are working to prevent the fire reaching trees and bushland.
Residents on a nearby street have been evacuated and there is a large exclusion zone in place around the fire, a NSW Police spokeswoman told AAP.
Traffic has been halted on the M1 motorway in both directions.
The NSW Environment Protection Authority has been called to the scene in a bid to stop more fuel running into drainage systems.
Images posted on social media show massive flames erupting from the tanker which is parked on the side of the road.
Sydney's west is forecast to reach the mid-30C while the mercury is tipped to hit 45C in other parts of the state on Friday.