More than 30 Tory MPs are urging ministers to change a bill to ensure leaseholders in England will not have to pay for emergency fire safety work.
The government’s Fire Safety Bill – introduced to strengthen regulations following the Grenfell Tower fire – returns to the Commons on Wednesday.
Conservative Stephen McPartland warned owners could face repair costs of up to £50,000 if the bill is not changed.
But No 10 has hinted it is unlikely to accept his amendment.
A Downing Street spokeswoman said: “We think the package we have come forward with is the right balance and will sort this issue for them and their constituents.”
Following the Grenfell Tower fire in 2017, which killed 72 people, many blocks were found to be unsafe and thousands of flat owners have since faced huge bills to pay for repairs.
Earlier this month the government announced it was putting £3.5bn towards removing unsafe cladding from buildings over 18m high.
This comes on top of a further £1.6bn for cladding removal announced last year.
The government also said owners of flats in lower-rise blocks would be able to access loans to cover repaid work – and that they would not have to pay back more than £50 a month.
However many MPs are worried the government’s Fire Safety Bill does not provide sufficient protection for owners.
Conservatives Mr McPartland and Royston Smith argue that the bill as it stands would allow freeholders to pass on costs to leaseholders.
Writing on his website Mr McPartland also says the £50 repayment cap covers cladding repairs but not other costs such as increased insurance premiums or work to install sprinkler systems.
“Leaseholders are being bankrupted by these costs in all our communities and cannot sell their properties with these debts attached,” he says.
“We cannot abandon leaseholders to the crippling costs of massive insurance premiums, waking watch and remediation of defects which were not deemed unsafe when they bought their property.”
The backbench amendment – tabled by Mr McPartland and Mr Smith – has support from Labour who said the government should “do the right thing”.
Shadow policing and fire minister Sarah Jones said: “This is an opportunity for the government to finally put the public’s safety first and to deliver on the promises it has made to leaseholders.
“Blameless victims of this crisis, who are living in dangerous homes and facing financial ruin, expect nothing less.”
Although the amendment has support from opposition MPs, the government’s large majority – and the fact that only English MPs can vote on the bill – mean it is unlikely to pass.