Metro Petroleum in Barrier Street will host the Canberra launch of app Go2 Rewards on Wednesday and will discount $1 per litre between 12pm and 2pm. The station has been selling petrol for close to 109¢ per litre this week.

The promotion is to launch app Go2 Rewards in Canberra, which rewards users with fuel discounts for shopping at partner businesses

The service station already has some of the lowest fuel prices in Canberra, with fairly consistent lines of cars waiting to fill up.

The government is concerned the promotion may result in heavy traffic conditions similar to those seen when Costco opened its discount petrol station in Majura Park last year.

"The temporary arrangements will mean traffic travelling to Metro Petroleum will need to access Barrier Street from the Newcastle Street entrance and exit via Ipswich Street," a spokesman said. "A reduced speed limit of 40km/h will also be in place."

The government also warned of possible changes to public transport with buses subject to diversions, depending on the traffic.

"Barriers as well as warning and diversion signs will be erected to alert people to the closure," the spokesman said. "Traffic marshals will also be on site to direct traffic."

Go2 Rewards founder Rick Firth said the app was created out of a desire to, "keep the bastards honest".

"Over half of the petrol stations are owned by Coles and Woolies. I believe they rip us all off," he said.

Mr Firth believes the app will help level out the playing field in the fuel industry by showing discrepancies between fuel prices and giving the public the prices in an easy to use app.

Go2 Rewards currently has 1080 businesses in Canberra on board, including Uber, Ainslie and Yarralumla IGA, Canberra Outlet Centre, Seears Workwear and Gymquip Fitness. Depending on the business, shopping can earn direct discounts or the chance to win discounts.