Nicola Sturgeon has said there "may well be" a case for putting the Brexit deal to voters for their approval once it has been decided.
The Scottish First Minister spoke out after condemning the ''xenophobic rhetoric'' of the Conservative Party conference in Birmingham, with Ms Sturgeon insisting she ''would absolutely stand full square square" with any company which refused to list foreign workers.
The proposal - which Ms Sturgeon branded "disgraceful" - was put forward by the Tories along with plans for more UK students to get access to medical degrees to reduce the NHS's reliance on overseas staff.
She hit out after warning MSPs at Holyrood the UK could be heading for the "hardest of hard Brexits'' under Theresa May's party.
The SNP leader later indicated she could be open to a second European referendum being staged once the terms of the UK's exit from the European Union (EU) have been negotiated
"I think there may well be an argument for that," Ms Sturgeon told a conference in Crieff, Perthshire.
She added that details emerging of any possible deal were "deeply troubling" because "they suggest that we are heading down a road of exit not just from the European Union but the single market".
Ms Sturgeon said: "I think there is a big job of work to be done at this stage to try and steer that in a different direction. I don't underestimate how difficult that is going to be."
She had earlier used clashes at First Minister's Questions at Holyrood to hit out at the "xenophobes" in the Conservative Government.
On the question of immigrants, she insisted we ''should value people by the contribution they make here, not by where they were born or indeed the colour of their passport''.
The First Minister said work to achieve that ''is undermined by some of the rhetoric we've heard from the Tory conference this week''.
She told MSPs: ''Nigel Farage said yesterday that virtually everything that Theresa May said in her speech were things he had said over the last few years.
''I do think all of us have an obligation to stand up against intolerance, against prejudice, against discrimination and against xenophobia in all of its forms, and I hope everybody in this parliament will do so.''
She attacked the proposal for companies to be required to state how many overseas workers they employ, saying: "What I found particularly offensive was the idea that companies would be named and shamed for the foreign workers they employ as if there was something shameful about employing workers from other countries. It is absolutely disgraceful.''
The First Minister went on to state: "People who have come from other European countries, or indeed from any country, and chosen to make Scotland their home and make a contribution here are welcome here."
She added: ''Unfortunately, and it is a matter of real regret to me, I do not have the power to guarantee the right of EU nationals to stay here in Scotland.
''What I will continue to do, and I hope I will have the backing of every single person in this chamber when I say this, is to call on the UK Government to stop using human beings as bargaining chips and give them the guaranteed right to stay where they belong here in Scotland.''