After last month's rejection of bids from Wollongong Wolves and Ipswich Pride FC, the six remaining candidates are Southern Expansion (NSW), Macarthur South West Sydney (NSW), Western Melbourne (Victoria), Team 11 (Victoria), South Melbourne (Victoria) and Canberra (ACT).

While O'Rourke hoped the new FFA board, to be elected later this month, could make a decision on the two successful bidders by the end of January, he said their entry might not happen until 2020-21, as revealed by The World Game.

"A number of bidders have said if they were to know in December or January, that would still be viable for them to come in the 2019-20 season, but any later than that would probably be too short a run-up," O'Rourke said on Monday.

"Their view is the longer they have, the higher quality team they can put together in respect of not having too little time to build a team.

"As a result of that, we would hope that by the end of December, the board would be in a position to make a call, if not the end of January at the latest."

Asked if that was the deadline for a decision for expansion in 2019-20, O'Rourke said: "It's not so much about the decision - it's about actually the timing of the entry.

"The decision itself could still be made (by then), but the timing of their entry could be delayed to give them an 18-month run-up instead of a six-month run-up."

O'Rourke identified the political situation in Victoria as one potential stumbling block in sticking to the time frame.

"There's one or two Victorian bids that require government support and the state government of Victoria is currently in caretaker mode," O'Rourke said.

"So until that government election is held (on November 24) and we can talk to the incumbent sports minister, treasurer, premier, that's something we can't control."

Asked if he would regard delaying expansion to 2020-21 as a setback, O'Rourke said: "I think the league would benefit from expansion in 2019-20, that's for sure.

"But if there's some obvious reasons to delay it for one year, not the decision itself but the implementation of it, I think most people would be slightly disappointed.

"But we'd be ready, knowing that one year - as long as we've got all the right questions answered - would be a reasonable timeline to make sure that was done."

O'Rourke said there had been formal meetings with some of the bidders about challenges identified in their documentation and the others would go through the same process probably by the end of next week.

Following those meetings, he said he was more confident about some of the weaknesses previously identified.