Brisbane's Clem 7 and Airport Link projects should have included light rail options, according to The Greens.

The party today proposed the city's Buz and CityGlider bus routes and busways be progressively converted to light rail to save on fuel costs and reduce carbon emissions.

The former Democrat turned Greens candidate for the seat of Brisbane, Andrew Bartlett, said the $4 billion Airport Link tunnel was a good example of misguided transport infrastructure.

''The inner northside has been devastated by these massive tunnels," he said.

"Windsor, Lutwyche, Wooloowin, Kedron [and] Kalinga have all had enormous impacts, which involve spending billions of dollars based on a business case which demands increased private car vehicle usage to be profitable."

While both the Airport Link and Clem 7 tunnels are used by buses as well as cars, Mr Bartlett said dedicated light rail was more effective.

The Greens leader Bob Brown and Senate candidate Larissa Waters joined Mr Bartlett today at the party's light rail proposal launch in Brisbane's Anzac Square.

Ms Waters called for Australia's senior infrastructure organisation, Infrastructure Australia, to review south-east Queensland's busways.

She said they should "extend out some of our heavy rail with additional light rail to make sure that some of our outer suburbs have a good public transport service as well".

Ms Waters said commuters in Brisbane's outer metropolitan suburbs faced higher costs to use public transport.

"It is those folk in the outer suburbs that are really being squeezed with cost of living pressures, and they don't have a lot of other options," she said.

Senator Brown said The Greens did not advocate replacing all buses with light rail.

"You will always need to have buses to complement light rail, as with all rail services around the world,'' he said.

The Greens will push for extra funds for public transport via the Senate if they win a majority in Saturday's federal election.