A monorail is the centre piece of the new draft $2.5 billion master plan for the Brisbane airport.

The Brisbane Airport Corporation (BAC) has today released its new plan, which includes a monorail linking the domestic and international terminals with car parking areas.

Construction is expected to start within the next 10 years.

BAC spokesman Mark Willey says the airport needs to cater for a huge increase in traffic over the next 20 years.

"We did some benchmarking with other international airports and typically airports of between 30 and 40 million passengers a year have a mass transit system connecting their terminals and Brisbane at the moment has about 22 million," he said.

"Within the 20-year timeframe of this master plan, those passenger numbers will grow to about 48 million."