A close West Australian community is in shock after four children and three adults were found dead after a shooting at a rural property in the Margaret River region of Western Australia.

Police have confirmed they found the bodies at a property in the tiny winery and beach town of Osmington, 227km south of Perth.

In the worst mass shooting since the Port Arthur massacre in 1996 – in which 35 people died and another 23 were seriously injured –investigators said they were treating the deaths of seven local residents as a murder-suicide.

“This is a horrific tragedy,” WA Police Commissioner Chris Dawson told reporters at a media conference on Friday.

“I don’t think any other words can really further describe how tragic this is. The loss of any life is tragic but four children and three adults, this is a significant tragedy.”

Federal MP for Vasse, Libby Mettam, whose seat incorporates Margaret River, told the ABC the deaths had already sent “significant shockwaves” through the town, and the community was hurting.

“This is a much-loved family, a big part of the Margaret River community,” she said.

Two firearms were found at the scene and police said victims suffered gunshot wounds.

“It appears that gunshot wounds are there but I don’t want to go further than that,” Mr Dawson said.

“We are trying to locate other members of the family and friends.
 I’m not in a position to release any further details of the identity of the deceased.”

He said the close Osmington community would be reeling but was confident it would rally together.

“This devastating tragedy will no doubt have a lasting impact on the families concerned, the whole community, and in particular, the local communities in our South West,” he said.

Employees at several local businesses in the Osmington and Margaret River area expressed their shock at the scale of the tragedy.

Police were called to the rural property at 5.15am (local time) by a man with a connection to the property, Commissioner Dawson said.

He would not release details of the call.

Police said four children and one adult were found inside a home on the property and two adults were found deceased outside close to the building.

The ABC is reporting former councillor and neighbour Felicity Haynes said the family, who had moved three years ago from Margaret River to start a farm, were “caring neighbours”.

“They were just such lovely people,” she told the ABC.

“They were a very socially-aware family, doing their best to create a safe community, and that is why it is so shocking to think that could be destroyed so quickly.”

Commissioner Dawson said he expected investigators and other specialists to remain at the property for several days.

“This will be a very large scale and detailed investigation but, importantly, from the information I’ve been briefed on, we have no present information to say that there is any other public safety concerns at this point in time.”

Asked if neighbours would be contacted for information, Commissioner Dawson said police would be immediately concentrating on the actual scene itself.

“As matters are further investigated, naturally, we would be asking for anyone that does know anything about this matter to contact police.”

Police will call in pathologists, clinical psychologists, chaplains and counsellors to support local police. Photo: ABC News

Osmington, with a population of 346, consists of a handful of roads, farms, vineyards, holiday chalets and a small Anglican church.

“I’m confident that the community will rally together but we’re also very well aware that there’s a lot of support services which we will be providing,” Commissioner Dawson said.

“We’ll do as much as we can from a police investigation point of view but, importantly, communities rally together in such tragedies.

“These tragedies have a lasting impact.”

Detectives from the Major Crime Squad have travelled to the town as part of the investigation, the ABC is reporting.

If you or anyone you know needs help, please contact Lifeline on 13 11 14 or beyondblue on 1300 224 636.