Former shadow home secretary David Davis says the government is heading for a "problem on a major scale" if it fails to scrap control orders.
The orders, part of counter-terrorism legislation introduced in 2005, restrict suspects' freedoms and are being reviewed by the government.
But there are reports that the review has recommended control orders be kept.
Tory Mr Davis told the BBC about 25 Lib Dem MPs and possibly as many Tories would oppose moves to keep them.
Control orders - in which terrorist suspects are placed under close supervision some compare to house arrest - were brought in to replace the detention without trial of foreign suspects, which the law lords ruled breach human rights.
Suspects are electronically tagged and can be subject to curfews, have their movements restricted and be banned from using computers or mobile phones among other measures.
The previous Labour government argued it had to control some suspects who could not be prosecuted because secret intelligence is not allowed in British trials.
Before the election the Conservatives had pledged to review control orders while their coalition partners the Lib Dems promised to scrap them completely.
When they entered into coalition they ordered a review, which has been carried out by the Office for Security and Counter-terrorism - that operates from inside the Home Office.
BBC home affairs correspondent Danny Shaw said the review was likely to conclude that 28-day pre-charge detention of terrorism suspects should be reduced to 14 days - but with strict bail conditions for an extra period, and that control orders should remain.
He said there was clearly tension between the coalition partners and although the review's conclusions had been passed to home office ministers, they still had to go to the PM, deputy PM and then the National Security Council, before the conclusions would be known.
Asked if the coalition was headed for a "car crash" over control orders, Mr Davis told BBC 2's Daily Politics: "It's certainly headed for a problem on a major scale, you've probably got 25 Lib Dem MPs who will find trouble voting for this, I suspect as many Tory MPs as well, maybe more. Certainly many more who are worried about it."
'Never never land'
Asked if the Tories were divided on the issue Mr Davis, who forced a by-election in his seat in protest at Labour's counter-terrorism measures, said: "There are different views on the issue and there are many people who think control orders should go, full stop, no ifs or buts, they should go."
He said counter terrorism strategy was failing - and control orders were a "disaster" that did not work: "This is not a very good policy and it has massive, massive negative repercussions."
His fellow Conservative MP Patrick Mercer, who used to chair the Commons sub-committee on counter-terrorism, said he opposed control orders but understood that "until we put other measures or legal instruments in place, I don't see any alternatives to them until such time as the law is substantially altered".
He said there were things that could be done to bring people to trial, rather than keeping them in "never never land" - such as allowing police to question suspects after they have been charged, using intercept evidence in court and US-style plea bargaining.
Lib Dem MP Tom Brake wrote to the PM on Saturday calling for the orders to be scrapped. He told BBC Radio 4's World at One control orders were not effective and people should have an opportunity to defend themselves in court.
He agreed with Mr Mercer that the law needed changing: "Let's look at, for instance, using intercept evidence ... there is much more that the government could do to make sure that these people come to trial and I think that is a basic principle of British justice and that is what should happen."
But he added: "I think I'm prepared to live with them [control orders] if there is a very clear end date by which legislation can be introduced to ensure that these other alternatives are available for use."
Lib Dem cabinet minister Chris Huhne restated his opposition to control orders in an interview on Sunday and Home Secretary Theresa May said no decisions on the review had yet been taken and denied she had been pressured into backing control orders by the security services.
But she added: "What I am clear about is that we do need to take some steps to rebalance national security and civil liberties but of course commensurate always with ensuring we can keep this country safe."
There have been reports that the former director of public prosecutions Ken - now Lord - Macdonald, who is overseeing the review, has written to Mrs May warning he would denounce any decision to retain control orders.
Mrs May told BBC One's Andrew Marr Show on Sunday Lord Macdonald was only overseeing what was an internal review to check "they have looked at the right questions and talked to the right people".
"That is the job Lord Macdonald is doing - but ultimately, the decision on what is in place in terms of our counter-terrorism legislation is a decision for government."