The First Minister and Labour leader Jeremy Corbyn will each tell Scottish union leaders at the STUC in Aviemore that their party represents the only challenge to the resurgent Conservatives.
Polling at the weekend suggested Tory support is rising north of the Border, with the party poised to capture a third of the vote and up to 12 seats – it currently holds only one.
Mr Corbyn is battling to avert his party’s worst election defeat in a generation as Labour trails the Tories by up to 20 points UK-wide.
Ms Sturgeon will say the general election in Scotland is a straight fight between the SNP and the Conservatives.
“The more Tory MPs there are, the heavier the price Scotland will pay,” she will tell union delegates.
“They’re already cutting nearly £3 billion from the Scottish budget. They’re hitting family incomes hard by cutting and removing child tax credits. They want to remove Scotland from the European single market, which will cost thousands of jobs.
“They’ve done all this with a small majority. Now they want to crush any opposition. The bigger the Tory majority, the more they will think they can do anything to Scotland and get away with it.”
A poll published by Panelbase yesterday had the Tories on 33 per cent in Scotland, the SNP on 44 per cent and Labour on 13 per cent. A separate poll by Survation found support for the SNP at 43 per cent, with the Tories on 28 per cent and Labour on 18 per cent.
Ms Sturgeon will tell trade union members: “The election in Scotland is a two-horse race between the SNP and hard-line Tories.
“The Tories have taken an extreme position, demanding an end to any opposition at Westminster if they win the election.”
She will say that a strengthened Conservative government will impose austerity measures including welfare cuts, and lead the UK to a “hard Brexit” without European single market membership or other trade deals in place.
The latest polling suggests it is unlikely that the SNP will recapture the 56 Westminster seats it won in 2015, although it remains on course for a comfortable majority of Scottish seats. But it could prove a difficult election for the Nationalists if they suffer losses of any high-profile senior figures.
The Tories are targeting the Moray seat of SNP Westminster leader Angus Robertson, which saw huge swings away from the SNP in last year’s Holyrood vote to Ruth Davidson’s party. The region was also the most pro-Brexit part of Scotland, with 49 per cent backing Leave.
The Perth and North Perthshire seat of Scottish affairs select committee chairman Peter Wishart could also be vulnerable after a big swing to the Conservatives in the equivalent Holyrood seat last year.
Meanwhile, in his speech to the STUC today, Mr Corbyn will insist his party can pull off a shock victory in the 8 June vote.
“Let no-one be in any doubt – we are in this election to win it,” he will tell delegates. “And we will fight for every seat in every corner of these isles.”
He will set out his plans for a £10 hourly living wage – which would hand almost half a million Scots a pay rise. He will also call on Police Scotland to open an inquiry into police activity during the miners strike of the mid-1980s.
Mr Corbyn will say: “The choice facing the country is clear. It’s the people versus the powerful. Labour will challenge the rigged system that is holding our country back. And just like trade unions, we will stand for the many not the few.
“Labour will never, ever apologise for the closeness of our relationship with the trade union movement – you are our family.”
But Mr Corbyn has a mountain to climb to reverse Labour’s ailing public support, with one poll showing half of all UK voters backing Theresa May’s Conservatives.
ComRes puts support for the Tories at 50 per cent – double that of Labour, on 25 per cent. The polling company said it was the first time any political party achieved 50 per cent support since April 2002, and the first time the Tories had reached that mark since January 1991.
A separate YouGov survey had the Conservatives on 48 per cent, 23 points ahead of Labour, while an Opinium poll puts the Tories on 45 per cent with a 19-point advantage over Labour. Only Survation had a significantly narrower gap, with the Conservatives on 40 per cent and Labour on 29 per cent, an 11-point difference.
The Tories welcomed the latest polling which suggests that the party is on course for the most seats in Scotland since the advent of devolution.
A party spokesman said yesterday: “The polls make one thing clear. Only the Scottish Conservatives have the strength and support to take on the SNP. Only a vote for the Scottish Conservatives will send the SNP a clear message: no to another independence referendum.”
The Liberal Democrats are also confident of making gains after the Survation poll had the party on 9 per cent. The party is targeting East Dunbartonshire and a number of seats in the north of Scotland.
Party leader Willie Rennie said: “We stand firmly against Scottish independence. So every vote for the Liberal Democrats is a vote for Scotland in the heart of the United Kingdom and Europe.
“Under no conditions can we sign up to Theresa May’s hard Brexit agenda, Jeremy Corbyn’s hard left programme or Nicola Sturgeon’s hard independence plan.
“This election is our chance to change the direction of our country. If you want to stop a hard Brexit, if you want to keep Britain united and if you want a real opposition, then Scottish Liberal Democrats are for you.”