Scottish Secretary David Mundell has urged MPs to vote down SNP plans for full fiscal autonomy for Scotland, saying the decision is a "bit of a no brainer".
Mr Mundell said the Scotland Bill, which is being debated in the House of Commons today, would give Holyrood £15 billion worth of new powers over income tax and VAT.
But he warned bringing in full fiscal autonomy - which would make Scotland responsible for raising all the cash it spends - would leave the country £10 billion worse off.
Mr Mundell insisted: "This Government will not accept amendments that are not good for Scotland. Full fiscal autonomy would be bad for Scotland - leaving us with £10 billion less to spend by the end of this Parliament.
"To put this number into context - last year the Scottish Government spent £10 billion on education and justice, this is everything from schools and colleges to our police force, prisons and court service."
Speaking ahead of the Westminster debate, the UK Government minister said: "The Scotland Bill will provide the Scottish Parliament with substantial tax and VAT powers worth around £15 billion and I look forward to discussing the tax sections of the Scotland Bill in detail with members across the House of Commons.
"This is a 'deal or no deal' moment for the fans of full fiscal autonomy. They can either vote for a more powerful Scottish Parliament that shares risks and resources with the rest of the UK or they can support a black hole plan that would cost Scotland the same amount as we currently spend on education and justice combined. Most people would consider this a bit of a no brainer."
As Mr Mundell spoke out SNP Westminster leader Angus Roberson urged Labour and Liberal Democrat MPs to vote with the nationalists over plans to transfer some control over welfare to Holyrood.
Mr Robertson called on anti-Tory parties to "come together" and back the amendments nationalists have put forward to the Scotland Bill.
These would remove any veto Westminster may have over new welfare powers that are being devolved to Scotland, as well as giving Holyrood control over working age benefits, benefits relating to children, and employment support programmes,
The SNP also wants control over National Insurance contributions, employment law and equal opportunities to be given to MSPs.
Mr Robertson said the votes would show whether Labour supported Scottish control or continued Westminster control in these key areas.
The Moray MP said: "At a time of savage cuts to the welfare state by the Tories - causing real hurt to hard working families and vulnerable people, and driving more and more people to food banks - the choice is between having welfare powers in Scotland's hands, or leaving them in the hands of Iain Duncan Smith and George Osborne. There is no other option.
"That is why the SNP's welfare amendments to the Scotland Bill are so important, and why Scotland needs the opposition parties to come together to support them. Labour will show where they stand - for Scottish control, or Tory control - and voting against the SNP's amendments or abstaining will signal that they prefer Tory control."
Meanwhile Labour shadow Scottish secretary Ian Murray hopes to change the Bill to give Holyrood the power to achieve an equal gender balance in the Scottish Parliament.
Mr Murray's amendment, if passed, would require a 50-50 gender split in the candidates put forward for Holyrood, with the Electoral Commission to determine the specific rules for making this happen.
The amendment would also make it the law that the boards of public bodies have the same number of men and women
Mr Murray said: "This is an idea whose time came many years ago. The fact is that despite good progress in the last decade there are still too few women in politics. Tinkering around the edges won't do the job any more. There needs to be bold and radical action to ensure equal representation of men and women in the Scottish Parliament.
"This isn't a party political issue. The cause of ensuring gender equality belongs to no one political party or movement. I hope MPs from all parties will be able to come together to vote for my amendment."
Labour has also tabled a number of amendments for welfare and taxation.
These includes a final say on benefits rates for the Scottish Parliament, unrestricted power to create new devolved benefits, a power to top up benefits, including in reserved areas, and the full devolution of housing benefit.
In the area of taxation, amendments include establishing an independent expert commission to assess the impact of full fiscal autonomy, and the creation of a Scottish Office for Budget Responsibility.
Mr Murray added: "Our amendments to the Scotland Bill have one single purpose in mind - to improve the lives of families in Scotland.
"They will secure the money available for public services and protect the most vulnerable people in our country. That was the original purpose of devolution and it's what we should be fighting for as we debate the Scotland Bill as the party of devolution."
Liberal Democrats leader Willie Rennie said: "Unlike the SNP, Liberal Democrats respect the result of the referendum and the historic all-party Smith agreement.
"Instead of seeking unity on breaking the Smith agreement I would urge the SNP to unite on the smooth implementation of the big, new powers on the way."