In a statement, WA Police said the man walked into a regional police station and "provided some information" which led police to attend the Coode Street home.
He added police were still examining the home for evidence and could not provide further details on the victims.
"Police have located the bodies of a number of deceased people including women and children", said Paul Steel, Assistant Commissioner for the Metropolitan Region.
The bodies of five people, including a woman and children, have been discovered at a suburban home in the Australian city of Perth.
'This is a tragic event and will have an impact on family and friends, the community, and the emergency services who first responded to the tragic scene.
There was no information about the ages of those who have died, beyond the fact some children were involved.
A number of police cars, homicide squad officers and forensic police are at the house.
Neighbour Vagner de Souza told the ABC he regularly saw a family in the house's yard. "It's just horrific on every level".
"The homicide squad now have teams of detectives on the ground, accompanied by specialist forensic police who are meticulously working their way through this crime scene".
"This is a very close community", she said.
It is also unclear how long their bodies had been inside the home before the grim discovery.
"We're all in complete shock".
"There are no on-going concerns for public safety as a result of this incident".
"I am deeply saddened by what had happened today", she said.
Shine Joseph said the roads were clear when he left his home on Fort Street this morning.
He did not say how the people were killed or if any weapons were found.
"It is a tragic thing when incidents like this occur", Asst Comm.
Peter Miles, 61, his 58-year-old wife Cynda, their daughter Katrina, 35, and her four children - daughter Taye, 13, and sons Rylan, 12, Arye, 10, and Kadyn, eight - were found dead at their Forever Dreaming Farm in Osmington on May 11.