A new Gold Coast franchise will enter the competition in 2011, with a club based in western Sydney to follow in 2012 and Demetriou said the league was open to expanding the current final eight format to include nine or 10 teams.
"We are looking at different models for the expansion," he told the Herald Sun newspaper in Melbourne.
"Is eight the right fit into 18? We haven't finalised that work yet."
The AFL has operated a final eight system since 1994, but Demetriou did not rule out switching to an odd number of finals participants.
"Why can't we do a final nine? We used to do a five," Demetriou said.
A move to a 24 round home-and-away season is also being researched, with Demetriou admitting the NAB Cup would likely make way. He denied the pre-season competition's disappearance from the schedule would cause any financial hardship for the league.
"We don't do the pre-season competition for revenue," he said.
"We do it to help us showcase the game around Australia, in capital cities and regional areas, to give rookies a trial, to give clubs a chance to showcase talent, to generate membership."
