New powers that would allow ministers to change laws without consulting Parliament must be watered down, an influential group of MPs says.
The laws are designed to allow red tape to be scrapped or changed
The government has already been forced to change the Legislative and Regulatory Reform Bill amid fears it would hand too much power to ministers.
But the public administration committee says concerns will remain until the amendments are outlined publicly.
Those changes will have to introduce restrictions on ministers, it said.
The bill aims to speed up the process by which redundant laws are changed.
It also allows laws to be amended on ministers' orders, without parliamentary scrutiny.
Critics of the powers say they could be used by a malign administration to remove crucial rights.
The committee says: "As currently drafted, the bill gives the government powers which are entirely disproportionate to its stated aims.
"The government has undertaken to amend it and must do so to ensure that by the time it leaves this House, it provides adequate safeguards against the misuse of the order-making powers."
Any amendments to the bill would have to introduce "real restrictions on the government's powers", the committee adds.
Earlier this month Cabinet Office Minister Jim Murphy dismissed as "wild accusations" claims that the powers could be used to scrap trial by jury or repeal the Magna Carta.
He said amendments to the bill would make it clear "beyond doubt" that its remit was limited to outlawing bureaucracy and would include some form of parliamentary veto.
The MPs welcomed that commitment, but said the minister had so far given "no indication of the nature or extent of the amendments".
"It is clear that the government will seek wide powers. We will not be able to judge the adequacy of any additional safeguards until we see precisely what is proposed."
The MPs said it was "all too easy" for ministers go back on previous undertakings not to use powers disproportionately.
"If government wants broad powers, it must accept that some matters must be off limits," they said.
The bill should exclude any power to amend the legislation itself or any other procedure relating to Parliament's operation.
But the MPs said the aim of the legislation was "widely, even universally, supported."
Mr Murphy said he hoped the changes would be ready for when the bill is likely to be debated in the Commons in mid-May.