Police are searching for a 12-year-old boy after three people were found dead in Central Australia.

Key points: Police believe a 12-year-old boy may have been in a vehicle that broke down near Willowra

Police believe a 12-year-old boy may have been in a vehicle that broke down near Willowra Land and air searches for the boy are underway

Land and air searches for the boy are underway Deaths are not being treated as suspicious

The bodies of a young family — a 19-year-old man, a 19-year-old woman and a three-year-old boy — were found yesterday about 4.5 kilometres from their broken-down vehicle near Willowra, 300 kilometres north-west of Alice Springs.

This morning police said a boy, who they believed was with the group, was not found among the dead.

"Further enquiries indicate it is possible a 12-year-old boy was a passenger in the vehicle and was not among the three people found dead," police stated.

"At this point in time we hold grave concerns for welfare of this child."

NT police were alerted to the deaths when a person walked into a local health clinic and raised the alarm just after midday yesterday.

Family members have not authorised the release of the child's name, but they told police community members in Ali Curung, Ti Tree and Willowra, who "are aware of his particulars".

Police are urging anyone with information about the child's whereabouts to call them on 131 444 or Crimestoppers anonymously on 1800 333 000.

Police do not believe the deaths were suspicious.

Young family last seen five days ago

Superintendent Jody Nobbs said the deceased were last seen leaving the community of Willowra five days ago, on November 2.

He said they were heading towards Jarra Jarra community, which was 18 kilometres from where the vehicle was found.

The three people who died were a young family, but police have not said if the 12-year-old boy was also related.

Superintendent Nobbs said remnants of food and water were found in the car.

He did not say how the person who alerted authorities was aware of the deaths.

But he said this person would be critical to the investigation and was "quite distraught from what he's found."

He did not say how the car broke down or when it likely broke down.

Two other deaths in past fortnight

Earlier today, Duty Superintendent Shaun Gill spoke to ABC Radio Darwin as investigators were still driving back from the Jarra Jarra Access Road, about 62 kilometres from Willowra.

"One of the avenues we're looking at is that they've walked off from a vehicle in extreme weather and may have got caught out," he said.

"Initially we thought it was the result of a car crash, however we're confident it's not.

"We don't believe the circumstances are suspicious."

Police will continue investigations and prepare a report for the coroner.

"This does serve as a timely reminder to anybody travelling on the Northern Territory roads, when you do travel, your vehicle is in a fit state for travel," Superintendent Nobbs said.

"And that you have sufficient supplies including water and a first aid kit, and someone is aware of what your travel itinerary is."

On Saturday, Daniel Price died on an isolated track near the Gibb River Road, in the Kimberley.

On October 27, a 27-year-old man died during a hike in Western Australia's mid-west region.