There is a provision in the NRL's new broadcast agreement that allows for the introduction of a new team, stipulating that it must be from Queensland.
But Greenberg said the NRL had no expansion plans.
"There are some pretty strong Queensland teams at the moment, that was evidenced last year in the grand final (between Brisbane and North Queensland)," he said.
"But I think we have made it clear our focus is on 16 teams and the sustainability of those 16 teams."
ARL Commission chairman John Grant agreed.
"We have 16 teams, that is the right number for our competition," he said.
"If you look at it from a participation base there could be more representation in Queensland but nothing is on the agenda on the moment.
"We haven't a timeline - expansion is not on our agenda."
Grant and Greenberg were at Thursday's opening of new headquarters Rugby League Central, Queensland opposite Suncorp Stadium.
The office will feature more than 100 NRL, QRL, Men of League and Touch Football staff as well as historical and interactive displays, function areas and a media centre.
"We will look back at this day and say what a fundamental decision it was for the game - it's a great day for rugby league in Queensland," Greenberg said.
- AAP