Father and son fugitives Gino and Mark Stocco face possible murder charges after a weeks-long manhunt by heavily armed police ended with their arrests and the discovery of a man's body at an isolated property in central western NSW.

Police have revealed a tip-off about a missing man led them to the property at Elong Elong, near Dunedoo after a search spanning three states.

Gino, 57, and Mark, 35, wanted after allegedly shooting at police in NSW, struggled as they were taken into custody and sustained minor injuries, but no shots were fired.

The body of the man found after the men were arrested is believed to be that of a 68-year-old who has been missing since early October.

The cause of his death is not yet known.

Gino and Mark Stocco were arrested at a property near Dunedoo. ( Supplied: NSW Police )

Acting Assistant Commissioner Clint Pheeney said police were treating the death as a murder investigation and a crime scene had been established at the property.

Acting Assistant Commissioner Pheeney said police had visited the property before but that the tip-off from a member of the public led them to mount a 16-hour stake-out before moving in to arrest the pair.

They believed the Stoccos had been there for a number of days, he said.

"Contrary to some media reports, they did not surrender to police or hand themselves in. They were arrested, following the property they were in being surrounded by tactical police," he said.

Mark Stocco in police custody at Dubbo police station. ( Supplied: Nine News )

"There was some resistance to the arrests and as a result of the arrest, some minor injuries, which are still being assessed at Dubbo base hospital, for both parties, both Gino and Mark."

He added: "We believe that they actually had been conducting some work there at the premises. But as to the actual nature of that, we are still investigating what those arrangements were."

Acting Assistant Commissioner Pheeney said public assistance played an important role in the arrests, in particular the tip-off about the missing man.

"In fact, what it did is it put the final pieces of the jigsaw together in terms of this property. That is what led us to this property," he said.

"Even though we were aware of it, we had actually been to the property and visited it previously. And we think that occurred prior to them actually occupying it.

Sorry, this video has expired Workers forced off site as Stocco arrest unfolds

"But the telling point, I think, was a member of the community saying or telling us the story about a missing relative and a person who has not been seen for about three weeks."

Acting Assistant Commissioner Pheeney said despite the men's knowledge of the bush, it was only a matter of time before the arrests were made.

"If we look at the expanse of country out here, the number of roads that are sealed, unsealed, back roads, forestry trails, these people knew the bush, they knew the bush very well, they knew all the ways and times to avoid police.

"But it was always going to be a case, it was only going to be a case, it was only going to be a matter of time before we tracked them down."

The pair were taken to Dubbo Hospital for treatment before being taken to Dubbo Police Station for questioning.

The farm house where Gino and Mark Stocco were arrested near Dunedoo. ( ABC News: Joanna Woodburn )

Elong Elong property 'very isolated'

Elong Elong Rural Property Centre director Denise Male said she sold the property Pinevale, where the men were arrested, only last year.

She said it was an isolated property that backed onto the Goonoo State Forrest, which is traversed by many remote access roads.

"It's a very remote and private property," she said.

"It's a brilliant thing that police have tracked them down to that location, because it's very isolated."

Police have been running a major operation to capture the Stoccos since they allegedly shot at police with a high-powered rifle during a car chase in Wagga Wagga in NSW earlier this month.

A local roadworker said he saw a number of police and ambulance vehicles travelling up the road.

"I thought something must have been up, and yeah they kicked us off our job site and told us we had to get out," he said.

"And yeah, apparently it was the blokes who have been wanted for a long time. At least they caught them I suppose.

"In Warrumbungle Shire you don't usually see too much of this action going on."

They were on Australia's most-wanted list for a number of violent crimes and property offences in Queensland, NSW and Victoria.

Gino Stocco, 57, and Mark Stocco, 35, were wanted in a number of states for a range of offences. ( Supplied: NSW Police )

They were sighted at Gundagai in southern New South Wales on Saturday October 24, when they stopped to fill up a white Toyota LandCruiser with fuel, and drove away without paying.

NSW Police also received a report of a sighting east of Wagga Wagga in the morning on October 25 but had been unable to confirm it, they said.

There were also multiple sightings of the stolen vehicle in Victoria, including an unconfirmed sighting at Sale, in the state's south east, on October 24.

The men had likely been changing their appearance, including shaving their beards, police said.

They were also believed to have frequently changed the licence plates on the LandCruiser ute.

There was speculation the pair could have stockpiles of supplies and weapons throughout NSW and Victoria.

Police described them as "fairly resourceful individuals".