Scottish ministers have been urged to think about new laws to soften the “significant” impact of planned changes to the UK benefits system.
Holyrood’s health committee said the Welfare Reform Bill could mean cuts in payments to the most vulnerable people.
But it also warned there may not be enough time to bring forward separate Scottish legislation.
The UK government has strongly denied the reforms are targeting disabled or vulnerable people.
It says the changes under the Welfare Reform Bill, due to come into effect in 2013, will save £7bn in welfare spending and encourage people currently on benefits to go out and find a job.
MSPs will be required to vote to allow Westminster to legislate on the issue for the whole of the UK under a legislative consent motion, because parts of the bill relate to devolved issues.
The Department for Work and Pensions warned the SNP government against blocking the move, saying that may hit key policies like free school meals and the blue badge scheme for disabled drivers, which had been linked to existing benefits.
Issuing a report on its investigation of the Welfare Reform Bill, the Scottish Parliament’s cross-party health committee backed two aspects of the legislation – changes to data sharing and industrial injuries benefits.
But MSPs warned other changes could hit claimants, increasing pressure on homelessness and social care services and forcing disabled people to move home.
The committee also said it “recognised” concern from children’s groups that the bill could plunge between 50,000 to 100,000 youngsters into poverty.
Its report concluded: “It is clear there would be significant reductions in the welfare benefits received by many of the most vulnerable people in Scotland, if the current proposals are implemented in full, and that this would be certain to have serious implications for the communities in which they live and the local economy.”
It added: “The committee acknowledges many of these concerns arise from a lack of detailed information, but, nevertheless, believes that they simply cannot be ignored.”
The health committee raised the prospect of the Scottish government bringing forward its own, separate legislation on the issue – but warned there may not be enough time to do so.
The report said: “The committee considered this approach may be preferable, as it would allow the Scottish Parliament more time to consider more fully to consider the implications of the forthcoming welfare reforms and the appropriate Scottish policy response to them.
“However, the committee is uncertain whether such a Scottish bill could be drafted, scrutinised and passed by the parliament in sufficient time to ensure that the Scottish statute book reflects the changes introduced by the Welfare Reform Bill prior to their implementation.”
The welfare bill, the committee also said, would still become law, even if MSPs voted against the legislative consent motion.