After preferences, the parties would be at 50-50, or even 51-49 to Labor, said the ACNielsen research director, John Stirton.
Not only would 21 per cent change their vote for a generic Crean substitute, a further 13 per cent said they might do so, depending on who it was.
'While votes would shift in several directions [if Mr Crean were replaced] the net impact would be to return Labor to roughly the position they were in at the last election, if not a little stronger,' Mr Stirton said.
'It is important to stress that this probably represents a best case scenario for Labor, as clearly the leader chosen will have a different impact to the generic replacement tested in this poll.'
Approval of Mr Crean's performance as Opposition leader has dropped 2 per cent from the previous poll, on May 16-18, to 28 per cent, and his disapproval rate has risen by the same amount to 58 per cent.
Mr Crean no longer even has a majority of ALP voters behind him. His approval rate in this group plunged 10 points to 40 per cent, a record low. This compares with 59 per cent in January. Forty-five per cent of Labor voters disapprove of the way he is handling the job.
I wish this poll had included the name of some alternative leaders. If Crean were to step down, and ultimately I think he must, replacing him with Kim Beasley might not achieve a great deal.