Cleaners and security staff at Brisbane Airport's domestic terminal are protesting over their pay and conditions, driving around the terminal in about 40 cars.

The staff are employed by cleaning contractor Spotless and security company ISS.

The protest is increasing traffic congestion at the terminal and Brisbane Airport Corporation says airport staff are on hand to make sure passengers get to flights on-time.

A spokeswoman says passengers on flights leaving Brisbane this morning should allow some extra time.