Contract laws allowing traders to refuse custom are a barrier to Scottish bank notes being accepted across the UK, the Scottish secretary has said.
Mr Bruce wants Scottish notes to become legal tender
Although a number of Scottish banks issue notes they are not backed by the force of law anywhere in the UK.
Des Browne told MPs at Westminster it was an "irritation" but Scots should keep insisting the notes were good.
His comments came after the issue was raised at Scottish Questions by Liberal Democrat MP Malcolm Bruce.
The only notes that carry the force of law are those issued by the Bank of England.
Mr Bruce, the MP for Gordon, told the Commons: "It is high time that Scottish bank notes were legally acceptable throughout the UK.
"They are authorised by the Bank of England and should have exactly the same status.
"If dollars and euros are acceptable to traders, surely Scottish notes should be."
Mr Browne insisted Scottish notes enjoyed exactly the same status as all other methods of payment under law.
However, he added: "I know some of my fellow countrymen have experienced, on occasion, the refusal of these bank notes.
"But I have been in London a lot over the last 11 years and because of ministerial responsibilities I have also had Northern Irish bank notes sometimes in my wallet and I have never experienced anyone refusing to accept them."
Liberal Democrat Alistair Carmichael told MPs newspaper research had shown that Scottish bank notes were often not accepted.
Mr Browne replied: "The fundamental problem here is that the law of contract across the United Kingdom allows people not to engage in a transaction at the point of payment if they don't want to.
"This irritation in the 21st Century shouldn't be here. The best thing to do is to take every opportunity to tell people that these notes are as good as anybody else's and should be accepted."