Two young girls have been found dead at a home in Madeley, in Perth's northern suburbs, and their mother has been arrested in connection with their deaths.

Key points: Two sisters aged six and 10 were found dead in their family home

Two sisters aged six and 10 were found dead in their family home Their mother was found with self-inflicted injuries at a nearby beach

Their mother was found with self-inflicted injuries at a nearby beach She is in policy custody in hospital but has yet to be interviewed

Police are at the home, in Bogdanich Way.

A police spokesman said the children were aged six and 10, and were found after police were called to the house about 6:00pm yesterday after neighbours raised concerns.

Assistant Commissioner Paul Steel said the children's mother had been arrested at Mullaloo Beach, about 12 kilometres away, at 8:40pm and was under guard in hospital.

It is believed she was found in sand dunes.

"It appears that she has self-inflicted wounds that are non-life threatening, and as a result she is not able to be interviewed at this time," he said.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 40 seconds 40 s The mother was arrested on nearby Mullaloo Beach with what appeared to be self-inflicted injuries.

He said the cause of the children's deaths would not be known until police and medical experts had thoroughly examined the scene.

He said the children's father was helping police with the investigation.

"The scene is quite complicated, there are a number of witnesses that are helping police, that have information to provide," Commissioner Steel said.

"The children's father is one of those people who's actually with police and we're trying to assist with his welfare as well.

"This is a tragic event and our heartfelt condolences go out to the friends and family of the children.

"Tragically for first responders, finding the bodies of two young children would have been a terrible thing to have to go through.

"We all have kids … it's actually the fact that we all have children in our lives that makes this so relatable."

The bodies were found at a house in Madeley, about 20 kilometres north of Perth's CBD. ( ABC News: Emily Piesse )

Children's deaths 'heartbreaking', police say

He said the event would "send a ripple through the fabric" of the local community and Western Australia in general.

"Heartbreaking events like this have an effect not only on those directly involved — the friends and family — but on the wider community of Western Australia," he said.

Homicide detectives were conducting a thorough inquiry, with the help of forensic police, who were "meticulously working their way through the crime scene".

Commissioner Steel said the family was not known to police.

He said further details about the family, including the mother's age, would not be released at present in order to protect the identities of the children.

Detectives set up an evidence collection station in front of the house. ( ABC News )

Part of Bogdanich Way was cordoned off on Saturday morning as detectives combed the property, which is in a new residential estate.

An evidence collection station and forensics tent was set up on the front verge of the house in the otherwise quiet neighbourhood.

Neighbour Paul Sherlock said most people in the area kept to themselves, although children often played together in the street.

Neighbour Paul Sherlock says people in the area are in shock. ( ABC News )

He said he did not know the family involved very well, but everyone in the area was in shock.

"It's young family area, everyone has young kids ... all working-class people, so it's a bit scary," he said.

WA Premier Mark McGowan described the events as "shocking, appalling, horrible, tragic" and said support would be provided.

"We'll make sure that there is support for children at the [victims'] school, psychological support and the like, but it's just one of those horrible, horrible things that sometimes occurs," he said.

"My thoughts go out to the family of the young girls."