The Sydney Morning Herald reports that a second team will be based in the western suburbs.
Demetriou spoke to reporters at the Sydney Cricket Ground before meeting with 35 AFL management staff to discuss strategies for growing the NSW and Sydney markets over the next 10 years.
"We've been very pleased overall with the sorts of numbers we've been getting in crowds in Sydney and in particular with our television ratings,” Demetriou said.
"Probably not in my lifetime at the AFL but I'm sure down the track I would be extremely surprised if there wasn't a presence in the western suburbs of Sydney.
"It's a long-term plan. We want to get the Sydney Swans firing and maybe even winning a Premiership."
The AFL in March committed to contributing A$2.5 million toward the 10,000-seat stadium in Blacktown's Olympic Park precinct in a joint venture with the NSW government, the local council and Cricket NSW.
The AFL plans to play pre-season games in the stadium by 2008.
Demetriou said the AFL was currently pouring about A$9million into NSW development, separate to what the Swans spend.
