Brisbane's Kingsford Smith Drive will be widened to six lanes by 2019, says Lord Mayor Graham Quirk.

After announcing details of a deal with the Queensland Motorways which would free up money for the upgrade, Cr Quirk said its complex series of staged payments would now let the work proceed.

"The beauty of this proposed deal that we have before us today is that we can go ahead with certainty now with the Kingsford Smith Drive project, and also stage one of Wynnum Road," he said.

Work on widening Wynnum Road, near Shaftson House at East Brisbane, would start by 2016, he said.