A car crash on the Pacific Highway has sparked massive delays for motorists ahead of Christmas.

A SUV reportedly rolled near the intersection of the Pacific Highway and Short Cut Rd in Urunga, on the NSW Mid North Coast, about 7.20am on Monday.

One passenger, a 32-year-old woman, was injured during the crash and rushed to Coffs Harbour Hospital in a serious but stable condition.

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The intersection of Pacific Highway and Short Cut Rd. Credit: Google Maps

Another passenger and the 37-year-old male driver were uninjured.

He completed a breath test at the scene which returned a negative result.

Police have launched investigations at the scene, closing northbound lanes along the major highway from the intersection.

It has since sparked a massive traffic jam stretching back about 20km to as far back as Hyland Park, Transport for NSW said.

“Ongoing police investigations are expected to take some time,” Transport for NSW said.

Motorists have been urged to allow for extra travel time and use diversions at Ballards Rd and Giinagay Way.

However, those roads are also being hit by heavy traffic while passing through the small town of Urunga, according to Live Traffic NSW.