Firms providing pensions across the UK may need to find millions of pounds to plug funding gaps if Scotland opts for independence, a report has suggested.
A paper by professional chartered accountants body ICAS raised a number of questions in relation to pensions.
The accountancy body also said information was needed about how state pensions would be divided up.
The Scottish government said pensions would continue to be paid in an independent Scotland as they are now.
The report said UK and Scottish ministers have a duty to "prepare a way forward" on pension arrangements in the event of independence.
It points out that EU rules mean deficits are not allowed in defined benefit schemes which cross national borders.
At the moment figures from the Pension Protection Fund (PPF) suggest 6,316 final salary pension schemes across the UK are currently running a £237bn deficit. ICAS said many had recovery plans but these stretch years into the future.
The independence referendum will take place on 18 September next year.
The SNP administration has previously stated that state pensions in an independent Scotland would be more affordable than they are in the UK.
The report, titled Scotland's Pensions Future: What pensions arrangements would Scotland need?, posed a number of questions for both the Scottish and UK governments.
- Who would make state pension payments in an independent Scotland and take responsibility for any entitlements built up prior to independence?
- Who would be responsible for unfunded public sector pension liabilities built up prior to independence?
- What pension regulation and protection arrangements would an independent Scotland need for private sector pensions?
- And how would EU solvency requirements for defined benefit and hybrid pensions schemes be met across the UK if Scotland became an independent country?
The 20-page report said that state pension payments were made from general taxation and were therefore unfunded. However, it added that entitlement was built up over many years.
It concluded that responsibility for that accrued entitlement would be a "major feature" of any formal negotiations between the Scottish and UK governments.
ICAS believed it would be "advantageous" for an independent Scottish government to continue in the early years with existing UK arrangements for pension regulation.
The body also identified "significant" cross-border issues for schemes which currently operate UK-wide.
It said: "Dealing with underfunding would have major cost and cash flow implications for employers with underfunded cross-border schemes."
The report added: "Given the extent of the challenges involved and the level of public interest in pensions, we would urge the Scottish government to begin the process of developing a robust plan for Scotland's pensions future before the outcome of the referendum is known.
"There would also be significant pensions issues for the UK government to address during any period of transition towards Scottish independence, which require scoping prior to the referendum."
Last month, the Scottish government said it was looking at pension plans in the event of independence after a discussion paper on the matter was leaked to the BBC.
Opposition parties believed the paper indicated that there would be a cut to pensions in an independent Scotland.
In response to the ICAS report, a Scottish government spokeswoman said: "At a time when the Institute for Fiscal Studies is warning that UK reforms to the state pension will leave the vast majority of people worse off in the long run, independence offers an opportunity to use Scotland's resources to properly support our elderly people.
"The Scottish government is already responsible for the majority of public sector pensions and independence will provide more fiscal levers to enhance affordability and sustainability.
"All pensions rights and entitlements which have been accrued will continue to be fully protected and accessible with independence, including private, public and state pensions.
"The cross-border management of pensions is commonplace throughout the EU, as underlined by the fact the UK has already introduced measures for cross-border schemes with Ireland. There is no reason why similar arrangements cannot be put in place for an independent Scotland."
Gregg McClymont, who is Labour's shadow pensions minister, said that the devil was in the detail when it came to pensions.
He added: "So far, none have been offered by the SNP. To state that nothing will change is simply not true and goes to show that the SNP continue to make it up as they go along.
"The introduction of the requirement of cross-border schemes to be fully funded has not been addressed. There needs to be clarity on this issue ahead of the referendum."
A Scotland Office spokesman said: "The best way to keep our pound and keep our pensions is to keep Scotland as part of the UK family."
ICAS, which has more than 19,000 members worldwide, said it takes a neutral stance on the issue of Scottish independence but recognised that it "had a duty to act in the public interest by contributing information and insights to the debate".
The executive director of ICAS, David Wood, said: "ICAS calls on the Scottish and UK governments to engage with business, the pensions industry and the EU to minimise the financial impact on these schemes, their sponsoring employers and the people who have paid into the schemes.
"Both governments have a duty to engage with citizens and other pensions stakeholders to prepare a way forward, in advance of the referendum, and agree transitional arrangements to be implemented in case of a 'yes' vote."