Police are investigating after bones, believed to be human, were reportedly found on the side of a road in a small town south of Adelaide.

SA Police said they were called to Paris Creek Road at Strathalbyn on Friday afternoon after reports that bones had been found on the side of a road.

Forensic investigators examined the scene, and returned this morning along with STAR Group officers, State Emergency Services volunteers and local patrols who have been searching the area.

The bones are believed to be human, but police said they will await the results of forensic testing. 

Paris Creek Road and Schmidt Road, which connect the towns of Macclesfield and Strathalbyn, were closed on Sunday morning but have since reopened.

Anyone with information is being urged to contact Crime Stoppers.