Southeast Queensland Labor backbenchers have circled August 31 as the most likely date of the federal election.

But if the election is not held then, they predict Prime Minister Kevin Rudd will avoid the September school holidays and football finals and run for office in October.

That gives Mr Rudd just this week to sort out important issues arising from today's special caucus in Sydney such as ALP membership and the stability of Labor's leadership, the MPs say.

The minimum campaign period for an Australian election is 33 days, meaning election writs are normally issued on the Monday after the weekend, five weeks before polling day.