Scotland's accountancy body has said there is no clear plan of how pensions would be managed if Scotland votes for independence.
Industry body ICAS said a "yes" vote in September's referendum could force "substantial" costs on employers with under-funded schemes.
It has also highlighted uncertainty over whether Scotland or the rest of the UK would pay some state pensions.
The Yes Scotland campaign has insisted pensions "will continue to be paid".
On 18 September, voters in Scotland will be asked the yes/no question: "Should Scotland be an independent country?"
David Wood of ICAS - the Institute of Chartered Accountants of Scotland - said: "These Scottish government papers have provided useful additional detail in relation to pension regulation and provision in an independent Scotland but some of our key questions remain unanswered.
"While we recognise that it will not be possible to answer every question prior to the referendum, nevertheless important questions remain on how legacy issues will be resolved and new arrangements will be implemented."
- There remains no clear plan as to how the Scottish and UK governments will work with the EU to minimise the impact of the cross-border funding rules on defined benefit schemes carrying deficits, which become cross-border schemes in the event of independence.
- The Scottish government's proposed three year transitional period for addressing pension deficits held by cross-border schemes is likely to be wholly insufficient as many UK employers currently fund scheme deficits over a much longer period.
- There are further questions about the feasibility of an independent Scotland sharing pension protection arrangements with the UK while establishing a separate pension regulator.
- There could questions over whether an individual's entitlement to a state pension at the date of independence would sit with an independent Scotland or with the UK. Similar issues arise in respect of entitlement to a pension from an unfunded public sector pension scheme.
Mr Wood added that ICAS had "taken a neutral stance in the independence debate".
Yes Scotland's website says: "On independence, people living in Scotland will be entitled to the Scottish state pension based on years of national insurance credits built up in the UK.
"From that point onwards, entitlement built up in Scotland will accrue to the Scottish state pension."
Yes Scotland claims there would be no change to private pensions after independence, as "private pensions are a private matter between individuals and their pension providers".
The campaign group added: "The Scottish government plans to establish a Scottish Pensions Regulator which would support a pan-UK approach to the regulation of private pensions and an integrated financial services market."
The pro-Union Better Together campaign described the ICAS report as "damning".
Speaking on behalf of Better Together, Labour MP Greg McClymont said: "ICAS are clear; there are no answers on who is responsible for your state pension, funding the multi-billion pound deficits or the future of the UK guarantee which protects Scottish savers."
Mr McClymont, who is Labour's spokesman on pensions at Westminster, continued: "The pensions system in the UK works well through the pooling of resources, where the risks are spread and the rewards shared across 60 million people.
"Why would we want to put the pensions of hard working Scots at risk?"
However, a Scottish government spokesman said: "Pensions are more affordable for Scotland than the rest of the UK, and will be fully protected and paid in an independent Scotland, and the single-tier state pension we propose will be worth more than the UK's.
"Cross-border management of pensions already takes place elsewhere in Europe as this paper acknowledges, and there is absolutely no reason why an independent Scotland would be in a different position to any other country in that respect."
The UK government said the ICAS report illustrated that "time and time again" the Scottish government had failed to provide the answers to the big questions on independence.
A spokesman for the Scotland Office added: "Despite the Scottish government's assertions that the White Paper would answer our questions on pensions, this report shows there are major unresolved issues when it comes to how cross-border schemes will work, who regulates and protects people's pensions, and where responsibility for state and public sector pensions lies.
"Scottish people deserve to know the answers."