Home Secretary Jacqui Smith has said the time has come to look again at extending the 28-day limit on holding terrorism suspects.
Jacqui Smith questions whether the 28-day detention limit is enough.
She told a fringe meeting at Labour's party conference prevention of terrorism outweighed any potential damage to community relations.
But Ms Smith ruled out extending the controversial period to 90 days.
Keith Vaz, chairman of the Commons home affairs committee, said the police must prove that they need the extra time.
At the fringe organised by human rights group Liberty, Ms Smith said extending the time limit needed to be considered because of the nature of the threat facing the country and the complexity of terrorism investigations.
Communities would not be damaged because of the judicial and Parliamentary oversight of detention.
"The biggest cause of conflict in our communities would be the impact that a successful terrorist attack would have on those communities," she said.
"It is entirely responsible for us to now take Parliament's view on extending the time limit beyond 28 days.
"What we are not talking about is a 90 day period, although I do believe it's right for Parliament to set a maximum time period for which a person can be detained without charge. We are not suggesting detention with no limit."
Ms Smith said she had to weigh up the need for developing cohesive communities with "preventing people who want to turn to violent extremism".
She said she genuinely wanted consensus on the issue, rather than being forced to "fast track" legislation through in the wake of a new terror attack.
Justice Secretary Jack Straw said there was a "world of difference" between extending pre-charge detention and the former use of internment in Northern Ireland, which he argued "acted as a recruiting sergeant for the IRA".
"If you don't have that balance you alienate groups and you find the effectiveness of the police withers away," he said.
But Mr Vaz said he did not believe there was an appetite among members of his committee to change the 28-day time limit for detention without charge.
"Parliament will actually need to be convinced with ministers coming out with the facts very clearly," he said.
"The police will have to make a better case. I think we will need to hear from the police that that 28 day period has not been enough when they have had to confront this new and dangerous threat."
The government had originally wanted police to be able to hold terror suspects for 90 days without charge - but was defeated in 2005 by a combination of Tory, Lib Dem and some Labour MPs.
A compromise eventually saw the previous 14-day limit extended to 28 days, but a number of ministers have said they still favour a longer detention period.