Nicola Sturgeon will demand powers over immigration this week as she tries to make Holyrood powerful enough to shape its own Brexit settlement.
The First Minister will outline her full plan to give Scotland with maximum access to the European Single Market, even if the rest of the UK cuts its ties, on Tuesday.
She warned that failure to agree to the proposals would mean a second independence referendum.
Ms Sturgeon said: “This is an important moment for Scotland – as the disastrous economic consequences of Brexit become ever clearer, it is vital that we find a way to protect Scotland’s interests.”
She added: “While we have of course not been involved in formal negotiations with other EU countries – that can only be done by the UK Government as the Member State – we have been busy ensuring that our position is understood by our friends and neighbours across Europe.
“But if our interests cannot be protected in this process, or are indeed brushed aside by the UK Government, then the people of Scotland should have the option of considering independence. That is why we are consulting on legislation that would allow another independence referendum to take place if necessary.”
Her proposals will include the devolution of immigration, business regulation, and employment rights to the Scottish Parliament, the Sunday Herald has reported.
Details of the plan follows Sturgeon’s establishment of an expert group, the Standing Council on Europe, to advise on the next steps for the SNP leader following the UK’s vote to leave the EU.
She claimed that a so-called hard Brexit would lead to tens of thousands of job losses and severely depress wage levels.
Ms Sturgeon said: “When I unveil these proposals on Tuesday, I will be very up front. The best scenario for Scotland’s future in my opinion would be as an independent nation and a full member of the EU.
“But after the referendum, I said that in the spirit of compromise and consensus, I would examine all options – not just independence – and these proposals fulfil that commitment.”
David Mundell, the Scottish Secretary, said a “team UK” approach would be best for the country, pointing out that issues over depopulation and single market access will apply to many parts of Britain, not just north of the border.
He wrote in the Sunday Times: “I hope this is wrong, but there is a fear Scotland will be told this week that its choice is essentially between a separate deal or a second referendum on independence.
“I doubt I am alone in my frustration at this approach because the truth is this: getting the best deal for the UK and making the UK work best is the best way to protect Scotland’s interests.
“I have spent the months since June 23 talking with businesses and industry groups across Scotland about their hopes and concerns — and the more work we have done, the more it has become clear that their concerns are not addressed through a separate Scottish deal.
“Take access to the single market. I know businesses in Scotland are concerned about this and it is a real priority. But it is just as pressing in Birmingham as Banff.”