Police are conducting inquiries into a fiery truck and car crash that has closed the Pacific Highway on the state’s North Coast this morning.

About 2.30am, a northbound car ran off the highway and hit a tree at Ulmarra, north of Grafton, before coming to rest in the middle of the road.

A 24-year-old Sydney woman and a young child escaped the crash with only minor injuries.

A short time later, a semi-trailer travelling north along the highway jack-knifed while trying to steer clear of the crumpled car.

The truck was unable to avoid slamming into the wreckage – bursting into flames on impact.

The male truck driver managed to free himself from the prime mover before it was engulfed in flames.

Police from Coffs/Clarence Local Area Command, Fire and Rescue NSW personnel, NSW Rural Fire Service volunteers and NSW Ambulance Paramedics responded to the incident.

The truck driver has been taken to Coffs Harbour Hospital for treatment of non life-threatening head injuries.

The woman and child have also undergone treatment.

Fire fighters extinguished the blaze a short time ago; however, the highway remains blocked in both directions.

Heavy vehicles are being diverted along Summerland Way between Grafton and Woodburn. Light vehicles are being diverted via the Tucabia – Tyndale Road.

Diversions are likely to remain in place for at least another hour.