TONY Abbott stands to gain control of the Senate on September 14, relegating Labor to its worst election result since 1901, according to a new state-by-state polling analysis.

New fears have spread through senior Labor ranks that the number two Labor Senate positions in a number of states could now be at risk with Labor's primary vote at or below 30 per cent in most states. And the union movement is becoming increasingly worried that unless Labor can maintain some influence in the Senate with the Greens, it will be powerless to stop the Coalition trying to crush the union movement.

An analysis of the latest polls, showing a primary vote of 29 per cent, suggests Labor could end up with only 25 to 26 Senate positions out of 76.

With the primary vote in the Senate traditionally three to five points lower for Labor than what it receives in the lower house, Labor stands to elect potentially just a single Senator from Western Australia and Queensland and just two in most other states.

With the Greens likely to end up with 10 to 11, Labor would not be able to exert any influence in the Senate.

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media_camera Federal Opposition Leader Tony Abbott / Pic: Jane Dempster

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The Coalition, in a worst-case scenario, would end up with 38, giving it 50 per cent of the Senate, and needing only one of several expected Conservative Independents to control both houses. "The Senate is the real story of this election," one senior ALP figure said. "This is where the fu- ture of the Labor party hinges."

The dire prediction for the Senate is being cited by senior Labor and union figures as another reason to support leadership change, with polls suggesting Kevin Rudd would lift Labor's primary vote and not simply save lower house seats but quarantine Labor from annihilation in the Senate.The analysis also suggests that Labor could end up with as few as 30 seats in the 150 seats House of Representatives - a result without precedent since 1901 when Labor commanded 14 seats out of 75 in the first Federal Parliament.

With a leadership showdown expected next week, Labor sources claimed last night Bill Shorten was telling colleagues he "needed more time". "We just hope he isn't deliberately trying to delay the inevitable."But Ms Gillard yesterday received public backing from key union figures, following claims Mr Shorten had been in discussions with them to push for her to stand down.

Australian Workers Union boss Paul Howes yesterday denied rumours that the union movement was softening in support for Ms Gillard.

media_camera Prime Minister Julia Gillard at the University of Western Sydney, Parramatta Campus / Pic: Craig Greenhill

Despite publicly calling for MPs to topple Mr Rudd three years ago, Mr Howes yesterday said his union would not direct MPs how to vote if a ballot was brought on next week.