Nicola Sturgeon has warned David Cameron that imposing Conservative trade union reforms in Scotland would be "unacceptable", ahead of a meeting in Downing Street.
The First Minister said she would set out Scotland's "clear opposition" to the Trade Union Bill when she meets the Prime Minister.
If passed, the Bill will introduce a threshold for strike ballots, new measures on picketing and will allow companies to hire agency staff to cover for strikers.
An attempt by the Scottish Government to block the UK-wide reforms from being enacted north of the border was rejected as ''not competent'' by the Scottish Parliament's presiding officer Tricia Marwick last week.
Speaking ahead of the meeting, Ms Sturgeon said: "There is clear opposition across Scottish society and across the Scottish Parliament to this damaging piece of legislation.
"The number of days lost to strike action have been reduced in Scotland by 84% through partnership working, not by slapping sanctions on workers.
"To impose this Bill on Scotland would be an unacceptable step and I will make that clear to the Prime Minister."
The discussions will also focus on co-operation between the UK and Scottish governments on security and intelligence in the wake of the terror attacks in Paris.
The Prime Minister said: "We know that Daesh pose a very direct threat to our country and our way of life. That threat applies across the UK and so it is essential that the UK Government and the governments of our devolved nations co-operate in the most effective way.
"We are looking at a number of issues, including the use of intelligence information, and we also need to ensure co-operation at a legislative level as well.
"We cannot afford to give terrorists safe spaces in which to communicate and we must give the police and security services the tools they need to keep us safe in the 21st century.
"I am hopeful that when we debate the Investigatory Powers Bill in the new year, we can achieve cross-party support for these fundamental concepts."
He insisted that the fiscal framework underpinning Holyrood's new tax and welfare powers would be fair to Scotland as discussions on the financial rules accompanying further devolution continue.
Mr Cameron said: "Both the UK Government and the Scottish Government are committed to getting a good deal for Scotland and these discussions are continuing in good faith.
"What I am absolutely clear on is that we must abide by the Smith principles - that is the promise we have made to the people of Scotland. This means that the fiscal framework must be fair to Scotland, fair to the rest of the UK, and built to last."
Ms Sturgeon said: "If the financial framework accompanying the new powers is wrong, Scotland could be worse off by hundreds of millions of pounds a year.
"The Smith Commission was clear that the Barnett Formula must continue unaltered, and that the Scottish or UK governments should be no better or worse off simply as a result of the transfer of powers - before any policy decisions are taken.
"It is absolutely crucial that future Scottish governments can use the new tax and spending powers, to create a fairer society and grow the economy, without losing out.
"Today is not about agreeing a final deal but I hope we can make significant progress in agreeing that the deal must be a fair one."