The ACT government has changed its pricing structure and will charge cars $10 to park on the east or west side of the stadium at Bruce.

The Raiders and Brumbies joined forces to go into bat for fans, writing a letter to ask government officials to reconsider the decision as Australian football codes fight to keep supporters in the stands.

Canberra Stadium has only increased its parking price twice in almost 20 years, going from $5 to $7 three years ago and from $7 to $10 next year.

The stadium will still be one of the cheapest parking venues in Australia, with some stadiums in Sydney slapping fans with a $20 or $25 fee.

There is also an olive branch to fans who turn up early. Anyone who arrives 45 minutes or more before the gates open will pay a discounted price of $7.

The move to charge $10 will effectively cover the cost of the government's new lease agreement after the Australian Sports Commission increased rent from a $1 peppercorn arrangement to $300,000 per year.

Assuming 5000 cars will use official parking for the 20 Raiders and Brumbies games per season, the government will pocket $300,000.

The government says the $3 rise will cover additional costs of traffic management and parking at the venue. The government also offers free public transport on buses for games at Canberra Stadium.

"We didn't take this decision lightly, a $10 fee across the country is still very low. We looked at several stadiums and did a lot of research," said Canberra Stadium manager Liz Clarke.

"There is the early incentive as well and that might avoid the crazy rush in the last 30 minutes to get people through the gates.

"It does offset [the lease increase] but our general fees have increased to have appropriate people at the car parks and safe car parks."

The Brumbies have slashed membership and ticket prices for the 2018 Super Rugby season in the hope of luring more fans to games.

Brumbies chief executive Michael Thomson said: "Our surveys continually tell us cost is one of the biggest challenges in terms of getting spectators to the game.

"We took that on board and dropped our membership prices, there will be a similar drop in game-day ticket prices. It's disappointing we are doing all we can to get more people there and have parking increase."

The Raiders already have more than 10,000 members and are keen to add another 10,000 to their books after Christmas.

The Brumbies and Raiders will play their first home games of the Super Rugby and NRL seasons less than 24 hours apart in March.

But the Canberra clubs are concerned any small increases in cost could be the determining factor for fans deciding if they will go to the games.

"It's disappointing for the fans because no one likes more expense," said Raiders boss Don Furner.

"I say all the time we've got the toughest fans in the NRL because they come out in the heat of March and the freezing nights in winter.

"Whatever we can do to get them out there is a must. I know there is an incentive to get people there early by offering the same price.

"But it was disappointing, we had a discussion with the stadium management about that and made our feelings known."

The government is waiting for the sports commission to make a decision on the future of the AIS and Canberra Stadium sites, and whether it will sell the ageing venues.

The government is keen to buy Canberra Stadium and the surrounding land as part of a long-term plan to either redevelop the Bruce site for sporting events, or selling the land to fund a new stadium in Civic.

Outgoing ARU boss Bill Pulver warned last week Canberra risked missing out on hosting rights to major events if the government did not build a new stadium with a roof in Civic.

The cost of taking a family to sporting events has been a bugbear for many years, prompting many to choose watching from home or a pub rather than going to the ground to watch the game.

The Raiders enjoyed their best average crowd figures in 22 years and the Green Machine is keen to build an even bigger following next year.

Brumbies crowds dropped, largely due to a confusing Super Rugby draw and Australian rugby's debilitating off-field turmoil.