The close-knit community, located about 20km from popular tourist destination Margaret River, has revealed their shock at the suspected murder-suicide.
The bodies of seven people, including 4 autistic children, were found near or at a farm property in Osmington near the South-western tip of Australia, confirmed Western Australia State Police Commissioner Chris Dawson.
The commissioner confirmed the person who made the call had a connection to the property but would not confirm the nature of the link.
Police said the deceased appear to be residents of the property but would not confirm their identity. Commissioner Dawson said investigators will be at the scene "for days".
Most recently Democratic representative Eric Swalwell (Calif.) penned an op-ed calling for a gun confiscation scheme similar to Australia's in the United States.
Gun violence has been rare in Australia since new laws were passed following a mass shooting in 1996.
Though strict, Australia's gun laws do allow for some exceptions. The National Firearms Agreement outlaws all of the semi-automatic weapons and pump-action guns.
Residents of the small Western Australian community of Osmington are in mourning after seven family members were found dead in a suspected mass shooting.
Samantha Lee, chair of the Gun Control Australia lobby group, said rural areas were over-represented in Australian gun deaths, including suicides. Police were led to the property by a phone call before dawn, Dawson said.
Its understood three generations of the same family lived at the Forever Dreaming Farm.
Detectives from the major crime squad are travelling to Margaret River from Perth.
Police said they have no information that would raise concerns about wider public safety, suggesting a shooter is not at large.
Police are still trying to locate next of kin and friends.
The ages of the children were not released.
Two firearms were found at the scene, and at least some of the bodies had gunshot wounds, authorities said.
Australia's last mass shooting was in 1996, when a lone gunman killed 35 people in Tasmania.
News.com.au has seen a social media post from someone who knew the family which said: "Lovely people, but insane ex-husband".
Former local councillor Felicity Haynes, who lives on a neighbouring property, said the family involved were "caring neighbours".
Dawson refused to be drawn on who the person was that alerted police, their relationship to the victims or whether they heard gunshots.