Labor won't support a move to increase the size of parliament despite analysts saying it's the only way all Labor MPs will keep their seats.
The Greens will tomorrow bring on legislation to restore the House of Assembly from 25 seats back to 35.
Premier Lara Giddings and Opposition Leader Will Hodgman have both said they will not support the expansion, which is estimated to cost more than $3 million a year.
Both Labor and the Liberal pledged to support the increase in 2010 but withdrew support because of budget constraints.
``We won't be supporting any moves to increase the size of parliament while revenues remain weak,'' Ms Giddings said.
Political analyst Kevin Bonham said returning to a 35-seat parliament would not change the outcome of the election but would put all Labor seats currently at risk back in the safe zone, including Ms Giddings's seat of Franklin.
``The Liberals would still certainly win a majority,'' he said.
Mr Bonham said the expansion would have the same life-saving effect for most serving Greens, although Braddon MHA Paul O'Halloran might not make even the reduced quota of 12.5 per cent of the vote if the federal election result was repeated in that seat.
The Greens statewide are polling at 13 per cent.
As it stands, Mr Bonham said Labor and the Greens are facing the loss of two seats each, with Mr O'Halloran, Bass Labor MHA Brian Wightman, Lyons Green MHA Tim Morris and possibly either Ms Giddings or Franklin Labor MHA David O'Byrne likely casualties.
Denison Liberal MHA Matthew Groom said the proposal was a ``cynical attempt by the Greens to save their own jobs by changing the size of parliament.''
Greens leader Nick McKim said the proposed legislation was about improving democracy, not sandbagging Greens seats.
``This is about improving the capacity for the parliament to make good decisions for Tasmania, and it's about a deeper talent pool for cabinet ministers so cabinet can make better decisions on behalf of Tasmania,'' he said.
Mr McKim said the estimated $2 million to $4 million cost was an ``insignificant amount'' compared to the democratic benefit.