Police say the deaths of a mother and her two children in Darwin property could be a double murder-suicide or a triple murder.

The body of a woman, 46, was discovered about 50 metres from a house on a half-hectare block on Saturday morning by the property owner, who called St John Ambulance crews and police.

The bodies of her 11-year-old son and seven-year-old daughter, were found inside a nearby tent at the Jingili property.

Detective Acting Superintendent Lee Morgan of the NT Police says officers are keeping an open mind.

“We’re considering this could be a triple murder. We’re also very conscious of the fact it could be a double homicide and a suicide,” Supt Morgan told AAP.

Two knives found on the ground near the mother are being tested for DNA evidence.

Police are not revealing the nature of the injuries.

Police are waiting on autopsy results expected to be completed within the next 24 to 48 hours to determine the cause of death, he said.

Supt Morgan said it is now believed the deaths could have occurred as far back as Tuesday.

“Given there was some serious decomposition of the bodies, we’d probably put it between Tuesday afternoon and Thursday lunchtime,” he said.

Police have established the mother did not have any known contact with anyone after Tuesday afternoon.

Supt Morgan said there were no suspects yet.

He said the children had different fathers, neither of whom are suspects.

He urged any witnesses to contact police.

* Readers seeking support and information about suicide prevention can contact Lifeline on 13 11 14 or Suicide Call Back Service 1300 659 467.