Mystery over remains found in burnt car

Detectives want to hear from anyone who may have seen a white Nissan Tiida in the days before it was found burnt-out by the side of a NSW highway with human remains inside.

The remains were found on Sunday morning in the car which was abandoned at a rest stop on the Cobb Highway south of Booligal.

"As our inquiries continue, we would like to speak to anyone who saw the Nissan Tiida in the 24 hours before it was found incinerated," Detective Acting Inspector Julia Bradley said in a statement on Wednesday.

"It is possible that someone may have seen the vehicle at the location either before or after it was burnt out - or they may even unknowingly have dashcam vision."

The remains have been examined and will undergo forensic analysis, NSW Police said.