Increased use of anti-terror stop and search powers could turn the public against police, the Lib Dems warn.
The laws give police more powers to stop-and-search
A survey by the BBC has shown a rise in the number of people being stopped and searched since the suicide bomb attacks in London on 7 July.
Lib Dem Home Affairs spokesman Mark Oaten said powers "should be used sparingly and be intelligence-led".
Police have defended their use of the new powers, while some forces say they have not used them at all.
Half of the 18 forces in England and Wales which responded to the BBC poll said they stopped more people since the 7 July London attacks than they had in the past year.
The powers allow police to stop and search people in certain designated areas without having to show they have "reasonable suspicion" an offence is being committed.
But Simon Cole, Assistant Chief Constable of the Hampshire force, which stopped more than 4,400 pedestrians and vehicles since 7 July, defended the use of the powers.
"We contain the home of the Army, the home of the Navy, lots of significant points of infrastructure; airports. Our job is to stop those places being attacked."
In 2003-4 the force stopped and searched fewer than 700 individuals.
Mr Oaten said: "If the numbers of searches continue to increase at this rate it will create tensions in communities, and could turn the public against the police."
Civil liberty groups also say there is huge scope for police to misuse the powers.
Not all forces have shown a sharp rise in stop and searches.
In Kent - a county that is home to the Channel Tunnel and the channel ports - there were just 56 stops and searches in the last three months, the survey showed.
Forces like Cumbria and Devon and Cornwall have not used the power at all.
Rob Beckley of the Association of Chief Police Officers told BBC Radio Four police were working with the Home Office to increase their accountability.
"The one thing we do recognise is the need for confidence in the way we use the powers," he said.
"We're looking at ways we can share the information and the intelligence that we use to make decisions about stop and search with the public a little bit more widely so they understand why we're doing it."
Lawyer for rights group Liberty Alex Gask said: "Usually there is a restriction on the police's power to stop and search because they need to have a reasonable suspicion that somebody is carrying a stolen item or has a weapon, or something along those lines.
"But with this particular power there's absolutely no need for reasonable suspicion at all - so there's nothing restricting the officers' use."
The government-appointed independent reviewer of terrorism legislation, Lord Carlile QC, said stop and search was a valuable tool but that it was being used too widely.
"It's unattractive to members of the public because it doesn't involve reasonable suspicion of anything.
"So one can be searched simply because one happens to be in a particular area."
In his annual review, Lord Carlile said overall the use of this power could be halved without any reduction in public safety.