Nick Clegg has rejected calls from three former home secretaries to revive plans for more data monitoring powers, after the murder of Drummer Lee Rigby.
The deputy PM warned the cross-party group against "knee jerk" reactions to difficult events.
He said proposals to store all website visits on a database were neither "proportionate nor workable".
A bill allowing the monitoring of all UK citizens' internet use was dropped after Liberal Democrat opposition.
But in a letter to The Times on Friday calling for it to be revived, three former Labour home secretaries, Jack Straw, Alan Johnson and David Blunkett, joined forces with two Conservative former cabinet ministers, Lords Baker and King and the Lib Dem peer Lord Carlile, the former independent reviewer of terrorism laws.
'Get right balance'
They said while they did not yet know whether "gaps in the current law" had been exploited in the Woolwich murder, terrorists had "access to global communications like never before".
The signatories of the letter said "coalition niceties" must not be allowed to get in the way of "giving our security services the capabilities they need to stay one step ahead of those that seek to destroy our society".
But Mr Clegg said on Friday that he rejected any claim that his opposition to the Communications Data Bill had endangered lives and said it was important to "get the balance right".
"We need to make sure the police and the security services have the powers that they need to keep us safe, that's why we are going to do some more work for instance on how you match IP addresses to mobile devices," he said.
"But we also have to get the balance right and I think that the proposal that every website that you visit should be stored on a database is not proportionate nor workable."
He added: "These former home secretaries will know from their own experience the dangers of knee-jerk reactions, over-the-top reactions, to the difficult events we encounter in this country."
He pointed to the history of Labour's efforts to extend the period terrorist suspects could be held without charge, first to 90 then to 42 days - both of which ended in defeat for the then-Labour government.
The Communications Data Bill would have given police and security services access, without a warrant, to details of all online communication in the UK - such as the time, duration, originator and recipient, and the location of the device from which it was made.
It would also give access to some details of Britons' web browsing history and details of messages sent on social media. The police would have to get a warrant from the home secretary to be able to access the actual content of conversations and messages.