A social media warning about a vehicle allegedly travelling the wrong way on the M1 near West Ballina was posted around the same time as a head-on crash that later left one woman in hospital.

In a post shared on Ballina Crime Reports about 9.25pm, Amalia Jobson said she was travelling south from the Ballina Travel Centre towards the Wardell turn-off when she saw a vehicle allegedly heading north in the southbound overtaking lane.

Ms Jobson said she had contacted Ballina Police after seeing the vehicle, but was told little could be done without the registration number.

According to Police, a Ford Ranger and a tow truck crashed head-on about 9.25pm.

An off-duty nurse stopped to help the driver of the Ford before NSW Ambulance paramedics arrived.

Paramedics treated the 48-year-old woman at the scene before taking her to Lismore Base Hospital in a stable condition.

Police said the 28-year-old woman driving the tow truck did not report any injuries.

Officers attached to Richmond Police District established a crime scene and an investigation is underway.

Police are urging anyone with information or dashcam footage to contact Crime Stoppers on 1800 333 000.