Drivers who use the M5 East Tunnel are in for a shock, with the air filtration system being shut down.

The New South Wales Roads Minister says it simply isn't working, so it will be shut down in a few months.

For the past 18 months the CSIRO has been analysing air samples from the tunnel, and according to Duncan Gay the filtration plant has made very little difference.

The $65 million system was fitted by the former government in 2010, due to community concerns about the pollution inside the four kilometre tunnel.

The Government's alternative strategy is to use cameras to track down the worst polluting vehicles, and to fix them, paying half of the mechanical costs otherwise drivers risk fines.

"Even though the effect is minimal we will continue to run the filtration plant for at least until the new scheme starts to take effect," Roads Minister Duncan Gay said.

Two months ago a Seven News investigation revealed the dangerous levels of pollution inside the tunnel, which forced the State Government to install pollution warning signs for drivers, and make internal test results publicly available.