The pair were travelling from Tonsberg to Alesund when their vehicle veered off the road and hit the railings after trying to avoid an obstacle.
They were still conscious when police arrived on the scene and were sent to the hospital as a precautionary measure.
Riise's agent Erland Bakke told Norwegian outlet Dagbladet: 'He drove her home to Ålesund, and just before they arrived, something on the road caused John Arne Riise to quickly turn left, and drive into the road rails.
'Both are well under the circumstances, they will remain in the hospital until this morning.'
A police statement read: “Report of traffic accident on the access road. One car involved, located on the side in the middle of the roadway. Two people in the car, both are out and conscious. Unknown extent of damage. Emergencies on the road.
“No major injuries, car not drivable. Examined by health professionals.
“Both involved drove the hospital for check. The road cleared and opened for normal traffic. The police make a case and question the involved witnesses.”
Riise spent seven seasons with Liverpool after joining them from AS Monaco in the summer of 2001.
The 39-year-old was part of the Reds side that won the Champions League in 2005, laying on the assist for Steven Gerrard’s goal that sparked the remarkable comeback from 3-0 down against AC Milan.
