Former prime minister Gordon Brown will focus on the security of people's pensions in an attempt to put forward the case for Scotland remaining in the UK.
The Labour MP is due to make a speech in Glasgow on Tuesday as part of a week of campaigning on the issue by the Better Together group.
Pro-independence campaigners Yes Scotland said most people want pensions controlled from Holyrood - and claimed that Scots have not forgotten Mr Brown's "tax raid" on pensions when he was in power at Westminster.
Mr Brown said: "In every speech since the referendum was announced I have argued that the strongest case for the union and the greatest benefit to Scottish people is that we pool and share risks and resources across the United Kingdom.
"In Glasgow I will present detailed findings from new research that shows the multimillion-pound financial dividend pensioners and families gain from our membership of the UK."
Better Together leader Alistair Darling, who was Chancellor under Mr Brown, said: " His 30 years of experience inform his powerful argument that Scotland can benefit from both seizing the opportunities that come from being part of the UK, and at the same time draw on the strength of that union.
"On pensions, Gordon Brown will argue the strong case for sharing resources across the whole of the UK. It means we are better placed to deal with challenges in Scotland in the years to come."
But Blair Jenkins, chief executive of Yes Scotland, said: " Almost two-thirds of Scots want decisions on pensions and welfare to be made here in Scotland rather than by Westminster.
"Time and time again, Westminster has failed Scots when it comes to pensions. People haven't forgotten Gordon Brown's tax raid on pension funds. And the current Tory changes to the state pension will, according to the Institute of Fiscal Studies, see the vast majority of pensioners worse off. That's why more and more people in Scotland are moving to Yes.
"With a Yes vote, we can build on the successes of the Scottish Parliament and continue delivering for older people with free personal care and the free bus pass."
The independence referendum is being held on September 18.
Deputy First Minister Nicola Sturgeon said Mr Brown "lacks all credibility" on pensions.
She said: "The last person anyone in Scotland will take lessons from when it comes to pensions is Gordon Brown - the man who destroyed final-salary pension schemes with his £100 billion raid, and insulted our older folk with a miserly 75p increase in the state pension. His track record means he lacks all credibility, and his speech next week sounds just like a rehash of what he has said before.
"The Scottish Government has set out clearly and unambiguously that people will continue to receive the pension entitlements they have built up - and any attempt to insinuate otherwise is grossly irresponsible.
"Opinion polling has consistently shown that people in Scotland want decisions on pensions and welfare to be made in Scotland rather than by Westminster - with the recently published Scottish Social Attitudes Survey showing that 63% of people want either independence, or 'devo-max', that would see only defence and foreign affairs remain in Westminster control.
"Social protection costs represent a lower share of tax revenues in Scotland than for the UK as a whole - meaning pensions are more affordable for Scotland.
"Scotland is better placed to afford our pensions and welfare than the UK - which is why Scotland's Future set out our plans to maintain the triple-lock, and set up an independent commission to look at the appropriate retirement age for people in Scotland."