Labour leader Jeremy Corbyn will address the first-ever Unite Scotland policy conference at a time of growing tension with the unions.
Unions are concerned about the impact UK Labour's nuclear weapons review will have on jobs while Scottish Labour has already voted to scrap Trident.
Labour is also fighting to hold favour with unions in Scotland, with many members defecting to the SNP and Scottish branches of major unions such as the RMT and the Communication Workers Union voting for independence in 2014.
SNP leader Nicola Sturgeon, Scotland's First Minister, and Unite general secretary Len McCluskey will address the conference on Sunday.
Scottish Labour has urged trade unionists to fight "SNP government cuts to council budgets" which local authorities fear could lead to 15,000 job losses.
Scottish party leader Kezia Dugdale is expected to say: "We know that investing in education is the most important economic policy we can have.
"If we can give every child and young person a world-class education then they, and Scotland, will be able to take advantage of the amazing opportunities the future will bring.
"We have a radical plan to ensure that every child, no matter their background, gets an education to prepare them for the opportunities of the future.
"Using the new powers coming to Holyrood we would implement progressive taxes on the richest few to invest £1,000 in every school for each child from a poor background.
"But we cannot begin to build a fairer, more prosperous country for those children while local services across the country are being starved of the resources they need.
"We cannot build a better life for those children when their parents are amongst the thousands of local government workers who have lost their jobs or the 15,000 more who Cosla say could go as a result of John Swinney's £500 million cut to our councils.
"We should be cutting the gap between the richest and the rest, not the budget for our schools and the workers from our services.
"I've joined Unite members and local government workers who have been lobbying the Scottish Parliament week after week on the cuts to local government.
"I am calling on all trade unionists to join Scottish Labour and speak with one voice to say these SNP cuts to local councils responsible for our schools and social care just aren't acceptable.
"We will fight these cuts in Parliament and we need trade unionists to fight them in town halls, in their workplaces and out in the community."
SNP MSP Linda Fabiani said: "Despite swingeing Tory cuts to Scotland's budget, Labour have spent the last few months calling for increased spending across the board – and have steadfastly refused to set out how this would be paid for.
"The fact is that in the current budget settlement, any increase in spending in one area can only be paid for through tax rises across the board or by cutting spending on other areas – Labour need to tell us which of these options is party policy.
"This year's budget process is the perfect chance for Labour to attempt to start acting like a serious political party and to bring forward fully-costed plans to show how their proposals would be paid for – and until Kezia Dugdale does that, her claims will continue to be exposed as transparent political games.
"The fact is people in Scotland don't even view Labour under Kezia Dugdale as a serious party of opposition, let alone a credible party of government - which is exactly why they now appear to be locked in a battle for second place with the Tories as we approach the election.
"In contrast to a Labour Party in complete disarray, the SNP in government is getting on with the job of delivering for Scotland as we reaffirm our commitment to build on the progress we've made in office so far, and continue to make Scotland a fairer, more prosperous place."