The most extreme scenario includes the Governor-General, Quentin Bryce, being forced to fly out of the country to protect the integrity of her office and NSW Governor Marie Bashir being drafted in to do her job.

Leadership speculation: Prime Minister Julia Gillard, left, and former prime minister Kevin Rudd. Credit:Getty Images

With the assistance of Anne Twomey, constitutional law professor at Sydney University, here are some of the scenarios:

1. Rudd takes the leadership and survives a no confidence motion on the floor of Parliament.

He would need the support of five of the seven crossbenchers. Tony Windsor has indicated Mr Rudd would not get his vote, while Rob Oakeshott and Peter Slipper have said they would decide if the situation arose. Kevin Rudd can count on the support of Bob Katter, Craig Thomson and Adam Bandt. In this scenario, Mr Rudd would be able to determine the date of the election and would not necessarily have to run to the polls.