The Scottish Trades Union Congress (STUC) is calling on Theresa May to make a six-point commitment to increasing Holyrood’s powers as part of the Brexit process.
General secretary Grahame Smith insisted it was incumbent on the Prime Minister to “recognise the different approach” being put forward in Scotland.
The STUC is demanding the UK Government entrench the rights of European Union (EU) citizens currently in Scotland, allowing them to remain living and working in the country.
It also wants the UK Government to negotiate a variated migration policy for Scotland, allowing the country to take a different approach from the rest of the UK.
Power over employment law and equalities should be devolved to Holyrood and MSPs should be able to increase the minimum wage if they want.
The STUC also wants the Scottish Government to be able to legislate on the right to work for refugees and asylum seekers while devolving more power over procurement could help create more apprenticeships and see more workers paid the living wage.
Mr Smith, speaking ahead of the STUC annual congress in Aviemore in the Highlands, said: “With a general election looming, it is vital that the trade union movement restates its position on Brexit and the protection of migrant workers.
“The STUC will continue to oppose hard Brexit and to campaign for free movement and the right of EU nationals living in Britain to remain in Britain.”
Motions being debated at the three-day congress “make clear the commitment of affiliated unions to inward migration and to the protection of migrant workers through legislation and trade union organising”, Mr Smith said.
He added: “We believe migration has an entirely positive contribution to make to Scotland’s economy, demography and culture, particularly in a properly-regulated labour market in which workers’ rights are protected.
“However, as it becomes increasingly clear that Theresa May is wedded to a policy of hard Brexit, it is incumbent on her to recognise the different approach advocated in Scotland towards migration and employment protection.
“UK immigration policy is increasingly encroaching on the devolved powers of the Scottish Parliament, including how it runs its public services and who works within it.
“Even with immigration reserved, it is clear that significant additional power could be vested in the Scottish Parliament.
“Along with powers to protect employment rights and increase the minimum wage, there is a potential to carve a distinctly different approach in Scotland.”