Independent MP Rob Oakeshott says federal Labor has 'rocks in its head' if the party thinks it can change leaders without it affecting the parliament.
Mr Oakeshott is one of four crossbenchers who backed Julia Gillard into minority government after the 2010 election.
Part of the agreement is for the parliament to run full term and for an election to be held in late 2013.
Speculation is growing that Ms Gillard may be dumped as Labor leader due to poor polling and replaced by either her predecessor Kevin Rudd or another frontbencher such as Bill Shorten.
The issue is expected to be on the minds of caucus members as they meet for a strategy meeting in Canberra on Sunday, ahead of parliament sitting next week.
But Mr Oakeshott said a leadership change could lead to the end of the Labor government.
'If the Labor party thinks they can make an old-style change of leader without it affecting the make-up of the parliament they have rocks in their heads,' he told AAP on Friday.
'They need to be sensitive to the make-up of the parliament and there are supply and confidence agreements in place.'
Mr Oakeshott said any incoming Labor leader should not automatically assume they could go to the governor-general and seek a snap election.
'We are obliged to sort it out as a group of parliamentarians,' he said.
Mr Oakeshott said all of the crossbenchers had written assurances from Ms Gillard of 'stable government' which mattered to him as it was the underlying principle of supply and confidence.
'If it is broken then we have full rights to consider all options,' he said.
'I am pretty confident there is more than one option to get to 76 (a majority of votes) on the floor of the house.'
It would be 'incredibly presumptuous' of Labor to think it could do what it wanted, Mr Oakeshott said.
