Strengthening the role of judges could be key to a deal on allowing terror suspects to be held for up to 90 days without charge, Lord Falconer says.
Ministers want to hold terror suspects for up to 90 days
The constitutional affairs secretary told BBC One's Sunday AM that judges could be given the power to order the release of a suspect at any time.
This would provide the safeguard critics want that the powers would not be misused, he said.
Both the Tories and the Lib Dems oppose the current 90-day detention plans.
The plans have also been criticised by senior judges and civil liberty groups as well as some Labour MPs.
As things stand the government faces a huge battle to get the proposal through both the House of Commons and the House of Lords.
Prime Minister Tony Blair insisted the police had put a "compelling" case for the detention laws.
At prime minister's questions on Wednesday Mr Blair said the complex nature of terrorism inquiries meant it was important to take suspects into custody "relatively early" and possibly hold them for longer so police could then "get the evidence necessary to charge them properly".
But Lib Dem leader Charles Kennedy said there was no "consensus" even within the government on measures, some of which were plain "wrong".
Currently terror suspects can be held for up to 14 days without charge.
Conservative home affairs spokesman David Davis said that he had been briefed by the police on their need for the new powers, but had not been persuaded.
He said that he would prefer a change in the law so that suspects could still be questioned even after being charged with an offence.
Liberal Democrat peer Lord Carlile, appointed by the government to oversee its anti-terrorism legislation, said he still had "concerns".
He wanted a "much tighter system of control", to ensure longer detentions were "justified...by evidence".
Lord Falconer said on Sunday that strengthening the powers of senior judges to oversee the process could meet Lord Carlile's concerns, and would be a central area for discussion over the plans.
He said: "If a reviewing judge took the view that the police were failing to provide a convincing explanation of the need to continue the detention, then the judge could order the detainee's release.
"That sort of oversight would ensure it would only be those very few cases where you need to keep somebody for 90 days, and you would be sure that it was done on a proper basis.
"That looks to me like finding a very sensible balance."