Bodies found in house near Adelaide

Police have refused to say if a murder-suicide or a triple killing is behind the deaths of three people in a small town north of Adelaide - but they have warned residents to be on their guard.

The bodies of a man, woman and teenage girl were found by an acquaintance inside a house in Harriet Street, Kapunda, 80km from Adelaide, about 11am (CDT) on Monday, police said.

Neighbours say couple Andrew and Rose Rowe lived in the rented house with their 16-year-old daughter Chantelle.

Major crimes branch officer-in-charge Detective Superintendent Grant Moyle told reporters at the scene it was too early to tell how the trio died.

"I'm not going to specify whether it's a triple murder or not at this stage," he said.

"There needs to be quite some extensive examination of the scene here before we can reach a definitive answer."

Supt Moyle would not say whether a killer was at large in the area, but called on the public to be watchful.

"I haven't suggested that (a killer is on the run) but I do appreciate that the public will be concerned in these things in these sorts of situations, so I accept that," he said.

"Again, it's just a matter of the public being vigilant about their own safety, their own security if that is of concern to them."

Detectives were hungry for information, Supt Moyle said.

"This is a small community and I'd ask that if any members of this community or anyone passing through the area saw anything unusual in this township or on the roadways to and from Kapunda, I'd just ask them to call police as soon as possible with any information they may have - no matter how trivial they may think it is," he said.

"It may be the vital piece of information we are looking for."

Police would remain at the scene for days, he said.

A police spokesman said relatives of the dead had been advised.

Kapunda is heralded as a gateway town to the Barossa Valley and Clare Valley wine producing regions.

It was first settled as a copper mining town in the 1840s and has a population of about 3000.

- AAP