More than 6,000 motorists have been caught speeding in Brisbane's new Legacy Way tunnel in a two-month period.

The ABC can reveal 6,223 motorists were fined for speeding on the toll road between July 1 and August 31 this year.

Among that number, 2,708 were caught in the Kelvin Grove section of the tunnel, while and more than 3,000 crept over the limit in the Toowong and Paddington sections.

Queensland Police Inspector Allan Hales said about 100 motorists a day are still being caught speeding in the tunnel, which opened to traffic on June 25.

"The percentage of high-end speeds, 40 kilometres plus over the speed limit, they're fairly high," he said.

"Obviously if someone is travelling at that speed they're creating a risk for themselves and others.

"There's advisory signs about the presence of cameras. Speed limit signs are displayed on each lane, I'm not sure what the drivers are missing."

Police said twice as many drivers are being fined for speeding on Legacy Way compared to Brisbane's Clem 7 tunnel.

Fines have ranged from $150 to more than $1,000, but Inspector Hales denied it was a revenue-raising exercise.

He said police had gone to extraordinary lengths to remind repeat offenders to hit the brakes.

"We actually rang those people and said you need to slow down, because they were going to lose their licence before the end of the week," he said.

Revenue from the fines is spent on road safety and the cameras are permanent fixtures in the tunnel, he said.

Steve Spalding from the RACQ warned drivers using Brisbane's toll roads and tunnels not to "set and forget" cruise control.

"For instance, you set the cruise control to 80 kilometres an hour the car will still vary by as much as 10 kilometres within a speed range," he said.