Police are appealing for witnesses to a fatal car crash at Ulmarra, near Grafton overnight.

About 6.40pm a Nissan Patrol with six people on board was travelling north on the Pacific Highway when the vehicle rolled.

A 19-year-old female passenger was taken to Grafton hospital in a critical condition but died soon after.

Two other passengers were trapped and later airlifted to Lismore Base Hospital.

At least two passengers were ejected from the vehicle as it rolled.

The Pacific Highway was closed in both directions for several hours.

Inquiries are continuing into the cause of the crash and a report will be prepared for the coroner.

Anyone who witnessed the crash is urged to contact the Ballina Crash Investigation Unit on 6681 8618 or Crime Stoppers on 1800 333 000.