When Tasmania's Symmons Plains Raceway first opened in 1960, it wasn't intended to be part of the V8 Supercars national circuit.

Northern Midlands farmer and motor sport driver John Youl developed the raceway on his property with the help of brother Gavin, good friend — and three-time Formula One world drivers' champion — Sir Jack Brabham and the Light Car Club of Tasmania.

"Longford was still operating at that time, but because it was a public road course it could only be closed for that one occasion," former Supercars track commentator Barry Oliver said.

"So the feeling was, with people in Tasmania spending money building cars and motorbikes to race, they needed another venue.

"They already had Baskerville down south, but they needed another venue up north."

Ironstone gravel from the western side of the Midland Highway — still the Youls' property — was used to build the track, as was dirt from the farm.

Once open, it didn't take long before the technical track — known for its tight corners and tricky hairpin bend — gained national attention.

In 1969, Symmons Plains was added to the Australian Touring Car Championship — now known as the Supercars — with the final round of the championship held there that year, and won by Norm Beechey.

John Youl's legacy living on

Andrew Youl says he is proud his dad's legacy is living on. ( ABC News: Manika Dadson )

Today, the Supercars is Tasmania's biggest sporting event and attracts more than 50,000 people to Symmons Plains over three days.

This weekend, the Supercars are celebrating 50 years of racing at the track.

The late John Youl's son Andrew said his family was proud his dad's legacy lived on.

"I think it's pretty special that we are celebrating 50 years this weekend, and I'm very proud that my dad was able to make that legacy with the help of a few other people," Mr Youl said.

"I imagine they have visions of it being a race track that people could race on and be an international racing venue.

"Racing was very different in those days, you used to get black-flagged if you put a wheel of the track — and obviously in those days we ran it as a farming property, so we used to run stock on there."

From paddock to famous raceway

Greg Crick says the track has changed a lot. ( ABC News: Manika Dadson )

Tasmanian motorsport legend Greg Crick, who has spent 43 years racing at Symmons Plains, said a lot had changed over the past 50 years.

"In the early days, when we used to come out here to a race meeting or to practice, you had to get the sheep off the track and if you were keen enough, you got the broom and you got the sheep manure off as well," Mr Crick said.

"The toilets were these disgusting long drops and every year they'd promise that they were going to build new toilets.

"I recall one year when the Victorian car team turned up and they didn't have new toilets — at the end of the weekend, mysteriously, a couple of transporters backed over all the long drops and knocked them over, so there was no choice but to build new toilets for next year.

"It was pretty agricultural in its day, but as you can see it's improved a lot over the years."

'Very technical' circuit

Sheep still roam in the nearby paddocks unfazed by the high-speed racing metres away, and the area is still prime agricultural land.

The track has been widened significantly since it was first developed.

It's also been resurfaced, has more run-off areas and much better safety barriers (in the 60s, safety barriers were timber rails).

There have only been three years in the past 50 that the supercars haven't held a round at Symmons Plains — between 2000 and 2003 when the track received a $3 million upgrade.

Mr Oliver said in the early days the pits never had garages, they were just an area of grass where spectators now stand.

The pits were then moved to the centre of the circuit, before the garages were later developed.

"The actual layout of the circuit has never changed," Mr Oliver said.

"Apart from a very small piece that was put in some years ago, strictly for the motorcycles to make it safer for them, but the cars don't use that part.

"People look at the circuit and think it's pretty simple. It's only 2.4 kilometres long.

Barry Oliver says the circuit is far from simple. ( ABC News: Manika Dadson )

"It's the shortest circuit in the championship; but as the drivers keep saying, it's very technical in places and if you don't get it right, all of a sudden you can go from [being] first to 20th, and that's why they keep coming here."

Mr Crick said it was a great facility now.

"It's thoroughly enjoyed by the touring car fraternity and the people that come here. It's now known as the bull ring because it's such a short, sharp exciting circuit," he said.