The SNP have backed a suggestion by a Labour think-tank to forge a progressive alliance to stop the Conservatives forming another government.
A study from the Fabian Society said that Labour must try to gain enough seats to form a centre-left coalition with other parties, claiming it has no chance of winning a majority at the next General Election.
The Nationalists have indicated they would get behind the proposal if it meant preventing another Tory Government at Westminster.
But Scottish Labour said the prospect of forming a “progressive” alliance with the SNP is “laughable”.
Bookmakers have slashed the odds of Theresa May calling a General Election in 2017, who may seek to win a personal mandate for her Brexit plans and capitalise on Labour’s weakness.
Asked if they would join Labour at Westminster to push the Conservatives out of office, an SNP spokesman said: “No one who is truly committed to delivering progressive politics would contemplate for one minute letting the Tories back into office, rather than work with the SNP.
“Labour lost the plot at the last election when they appeared ready to allow the Tories to remain in power rather than take up the chance of forming a progressive alliance in the Commons.”
In the run-up to the General Election in 2015, which saw the Nationalists nearly wipe Labour out in Scotland, Ms Sturgeon called on the then Labour leader Ed Miliband to lock the Tories out by joining forces with the SNP at Westminster.
Anas Sarwar, from Scottish Labour, said the SNP do not want an alliance with because they believe Labour’s “destruction and the continuation of Tory government in Westminster is the route to independence”.
“Repeated talk of a ‘progressive alliance’ is laughable. The SNP is not a progressive party,” he added.
“There have been no redistributive polices from the SNP in government.”
The Fabian Society report warned that Labour is on course to win as few as 140 seats in the next General Election, down from its current total of 231.
It said Labour leader Jeremy Corbyn’s unpopularity and a muddled approach to Brexit were key factors in the party’s troubles.
Mr Corbyn’s spokesman said the leader provided the “only genuine alternative to a failed parliament political establishment”.
He added: “Labour under Jeremy Corbyn will be taking its case to every part of Britain in the coming months with a radical policy platform.”
Meanwhile, Derek Mackay, the Constitution Secretary has said the option of Scottish independence “must stay on the table” as he urged people to respond to the Scottish Government’s consultation on its draft referendum bill, which closes on January 11.
