The bodies of man and a woman have been found inside a Melbourne house, with police treating their deaths as suspicious.

Police were called to the Heidelberg West property for a welfare check, after concerned relatives raised the alarm, just after 7pm (AEDT) on Sunday.

They discovered the bodies of a 50-year-old woman and 47-year-old man inside the house.

Homicide squad investigators are awaiting the results of a post-mortem examination to determine their cause of death.