Under Mr Rudd, Labor would attract almost 7 per cent more votes on a two-party-preferred basis, if the results of polling taken on Saturday in six key election seats were repeated across the country.

And less than 100 days before the election, if the party does not change leaders, the results of the September 14 vote are likely to be disastrous for members of the cabinet. At least three ministers would lose office.

Schools Minister Peter Garrett, Jason Clare, a rising star of the ALP who holds the portfolio of Home Affairs, and Trade Minister Craig Emerson will leave Parliament, according to the ReachTEL survey.

The poll is also a blow to the Prime Minister's personal standing. A third of respondents rated her performance as ''very poor'', while just 14 per cent said she had done a ''very good'' job.

The poll is almost certain to fuel further leadership speculation amid claims that Mr Rudd is running another last-ditch bid for the leadership, with high-profile campaigning and media appearances across the country.

A spokesman for Ms Gillard said she would not comment on the leadership speculation.

Mr Rudd said the matters had been conclusively dealt with by the caucus.

In Victoria, ministers Bill Shorten and Jenny Macklin would be safe regardless of whether Labor goes to the election with Ms Gillard or Mr Rudd as leader.

But their votes would improve in their respective seats of Maribyrnong and Jagajaga if Mr Rudd were to take the party into the poll.

In an irony given their well-known dislike of each other, the chances of Treasurer Wayne Swan holding his Queensland electorate of Lilley would receive a major boost if Mr Rudd was reinstated.

Mr Swan's two-party preferred result would jump from 53.0 per cent to 56.6 per cent with the former PM at the helm of the ALP.

The option of Mr Shorten as leader did little overall to improve Labor's election chances.

Mr Rudd attempted to hose the speculation down. "These matters have been conclusively dealt with by

the caucus and confirmed again by Mr Rudd's statements in the last 48 hours,'' his spokesman said.

''Therefore, the focus is no longer on the internals of the Labor Party, it is now on Tony Abbott and the Liberal Party's slash-and-burn agenda.''

Mr Garrett would enjoy a swing of 4.5 per cent with Mr Rudd, Mr Clare a swing of 8.4 per cent, and Mr Emerson a massive swing of 11.8 per cent.

But without Mr Rudd leading Labor to the election, they would all lose their seats, going by the results of the poll.

Ms Macklin's vote would improve 3.1 per cent under Mr Rudd, and Mr Shorten's vote would jump 8.6 per cent courtesy of the man he helped to topple as prime minister in 2010.

The most recent Nielsen poll showed the Abbott-led Coalition still had a strong two-party-preferred lead of 54 per cent of the total vote to the government's 46 per cent.

Strategists on both sides of politics believe the September 14 election will be decided predominantly in NSW and Queensland.

A March Fairfax Media/ReachTEL automated poll, taken in four safe Labor electorates in Sydney's west, has found much of Labor's collapse can be attributed to negative perceptions of Ms Gillard's leadership.

The automated phone polling firm ReachTEL uses Australian Bureau of Statistics and census data to identify people in the targeted electorates and weights responses to match the age and gender profile of the seat. Polling more than 600 people in six federal electorates across New South Wales, Queensland and Victoria, the margin of error is slightly less than 4 per cent.

The automated voice broadcast technology is used to collect poll responses so those surveyed are not pressured into ''popular'' answers, ReachTEL operations manager James Stewart said.