The cows do not seem too perturbed but they make sure they get out of the way whenever the members of the Busted Arse Tank Repairs and Co roll by on an armoured vehicle.

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These giant machines may seem out of place on the otherwise quiet, rural property near Oberon in central-west New South Wales.

But their owner said in the years following World War II, ex-military vehicles played an important role on many Australian farms and he and his band of tank tinkerers want to pay tribute to that history.

Matt McMahon restores and drives his collection of ex-military tanks. ( ABC Central West: Melanie Pearce )

The tanks that helped build the farm

Many sheds on farms across Australia are jam-packed full of dusty collections of tools, equipment and junk.

But the shed owned by Matt McMahon, a cattle producer in the Oberon district, contains some massive rusty specimens that speak of a little-known part of Australia's farming history.

It is a collection of tanks and other ex-military vehicles which was originally started by his father, John McMahon, in the decades following World War II.

"The Army had an enormous amount of them and they were sold off in the late 40s and early 50s [when] bulldozers were very hard to come by and very expensive," Matt McMahon said.

In the great tradition of farmers making do with what was to hand, many snapped up cheap ex-military vehicles at auction.

"I've read stories of people getting a whole row of them for 50 quid."

John McMahon using a converted tank to clear land on his farm near Oberon, NSW, circa 1973. ( Supplied: Matt McMahon )

Mr McMahon said tanks helped shape many Australian properties including his, where his father cleared land and built dams with a converted Matilda tank.

"You could go to an auction and buy a vehicle like this and it'd be the most powerful vehicle on your property and you could pull scrub and do all those sorts of things that are not so politically correct to do."

"Bulldozers and that type of machinery really didn't become available until around the time the Snowy Mountains scheme finished," he said.

Shane Casey, the Australian War Memorial's senior curator for Military Heraldry and Technology, said it is unknown how many farmers used ex-WWII tanks as farm equipment.

"We understand that this happened quite a bit, but I think that the extent to which it happened is pretty much unknowable [and] what people did to surplus army equipment on their own farms was unrecorded."

A tank bought by John McMahon after World War II and converted into a bulldozer. ( Supplied: Matt McMahon )

Preserving rusty relics

Mr McMahon now has around a dozen ex-military machines, including five Matilda tanks, a Centurion and three Bren Gun Carriers as well as several jeeps.

He and a group of like-minded enthusiasts gather most weekends to work on the historical hulks to bring them back to working condition.

"The group here is a loose association of friends and acquaintances called BATRAC International; that's the Busted Arse Tank Repairs and Co."

When they are not tinkering in the shed, welding and bashing the rust buckets into shape, BATRAC members take the tanks out for a run on the farm.

Often half a dozen or more adults and some children climb aboard and the vehicles power through the paddocks, only slowing so someone can hop down and open the gates.

The farm shed owned by the McMahon family near Oberon, NSW, houses a treasure trove of military history. ( ABC Central West: Melanie Pearce )

A passion for the past: increasing popularity

Mr McMahon said he and the members of BATRAC were not about glorifying war or playing war games.

"It's more about the tribute to the people, the men and women that made them in the late 30s early 40s and the task that they played in giving everybody the freedom that they now enjoy," he said.

It can be quite expensive to keep the military vehicles running.

"This one uses about six gallons an hour in diesel, we've got one down the shed there that'll use 13 litres of petrol every hundred yards," Mr McMahon said, patting one of his British-built Matildas.

Members of the Busted Arse Tank Repairs and Co keep ex-military vehicles in working order. ( Supplied: BATRAC International/Matt McMahon )

Although they are disarmed, the vehicles are still a crowd favourite at occasional commemorative events, however Mr McMahon said it was becoming a tricky task to manoeuvre for road authorities.

"Once upon a time we used to go to town every year and trundle up the street, but now it's become very difficult to get a permit," he said.

"They don't like tracked vehicles on the road even though these tracks hardly mark the tar at all."

With increasing interest from collectors and the difficulty of sourcing spare parts, working tanks have experienced a rapid growth in value in recent years.

"This vehicle, Dad paid $250 for it in 1972, now it would be worth somewhere around $300,000."

But for Mr McMahon the real value in the vehicles was that they reminded him of his father and the role they played in the creation of the family farm.

"It was something Dad really enjoyed and he was very passionate about as well — we're just keeping on the tradition I guess."