Police are trying to determine if two people found dead inside a townhouse in the Perth suburb of Innaloo were the victims of foul play.

The bodies of a man and woman, believed to be in their 30s, were found inside a townhouse in Donar Street early this morning.

Police say they were found on the ground floor of the home and it is believed they may have been dead for a couple of days.

The bodies remain inside the property as forensic police and officers from the Major Crime Squad try to determine how they died.

Neighbours say they did not hear anything suspicious last night and the property was unusually quiet.

Police say it may take several hours to determine if the couple were victims of foul play.