But the SNP administration hit back, insisting its White Paper had set out proposals for an "affordable, fair and efficient pensions system" in Scotland following a Yes vote.
In a report, the House of Commons Scottish Affairs Committee launches a withering attack on the SNP administration, accusing it of failing to cost properly its plans for both public and private pensions, which would leave the Scottish public with uncertainty in an area where most people value certainty.
The report says establishing a new benefits system by the 2018 deadline set by the Scottish Government just two years after independence is "over-optimistic" and will take much longer.
It suggests the SNP administration's plans to consider delaying the increase in the state pension age to 67 and to pay a proposed higher starting rate than the rest of the UK are almost entirely uncosted. The committee calls on it to give a clear proposal for a future pension age and the full price of its plans before the referendum, so "current and future pensioners can judge how much more expensive they would be".
On working-age benefits, the MPs say the Scottish Government's plans have failed to acknowledge the costs and complexities of disentangling Scottish claimants from the UK welfare system, and that establishing a new system would be costly, complex and not possible within its suggested timetable.
Labour's Ian Davidson, who chairs the committee, said: "Pensioners, current and future, deserve certainty. Instead, the Scottish Government offers no detail, no costings, no believable plan and what it is offering amounts to the biggest mis-selling scandal in history."
The Glasgow MP added: "The people of Scotland deserve more respect from the Scottish Government."
But a spokeswoman for the SNP stressed pensions and welfare were more affordable in Scotland than in the rest of the UK and that under proposals set out in the White Paper, Scottish pensioners would get a guaranteed pension of £160 a week from 2016/17, a triple lock and the continuation of savings credit. "Scotland's pensioners are being short-changed," she said.
Meantime, Eilidh Whiteford, SNP welfare spokeswoman, said a Yes vote would end the "pensions con" being perpertrated on Scotland by the Coalition and the Labour Opposition.
Noting neither had told pensioners whether the state pension would keep pace with the cost of living, she said: "Labour and the UK Government should set out their position on the future of the state pension."