Tony Blair was accused of arrogance and of attacking civil liberties as he defended his anti-terror plans ahead of MPs' first debate and vote on them.
Mr Blair is being accused of ramming through anti-terror laws
Tory leader Michael Howard accused Mr Blair of steamrolling the house arrest plans and of "using national security for political point scoring".
Lib Dem leader Charles Kennedy told MPs the plans were "authoritarian".
Mr Blair said national security was his top priority, and said the Tories were the ones playing politics on the issue.
MPs are now debating and will vote later on proposals to give the home secretary the power to order terror suspects to be held under house arrest without trial.
The new system of "control orders" could also impose curfews, tagging or bans on telephone and internet use.
They would replace current powers to detain foreign terror suspects without trial, which the law lords have ruled against.
Opponents say only judges, not politicians, should be able to order detentions, especially as the powers cover UK citizens for the first time.
Former Labour Cabinet Minister Frank Dobson said allowing a home secretary to impose house arrest undermined the "timeless rights of British citizens and our standing in the world".
The government is expected to win Wednesday's Commons votes, due about 2000 GMT, but it faces a struggle in the House of Lords.
Opening the debate, Mr Clarke told MPs measures were needed where prosecution was impossible.
Any control order would be reviewed by a judge, he promised, and for house arrests, the courts would have to decide within seven days.
'Learn by mistakes'
Mr Clarke says he does not intend to use the house arrest powers now - even for the 11 foreign terror suspects mostly held at London's Belmarsh prison.
The existing detention powers expire on 14 March.
Mr Howard questioned why Mr Blair would not consider renewing that legislation - something the Tories would support - or consider alternatives.
He said the government was "in the mess it's in" - because the current legislation "was rammed through Parliament" - and it should "learn from that mistake".
Mr Howard asked Mr Blair: "Why are you being so arrogant about these questions which are so fundamental to our security and our liberties?"
The prime minister said he was acting on the "unanimous" advice of the security services and police chiefs, who said the orders were "necessary to disrupt the planning of terrorist activity in this country".
The UK's security had to come first, he argued: "That's not simply what a responsible prime minister should do, but what a responsible leader of the opposition should do."
The Lib Dems say they are not opposed to control orders in principle, but want decisions taken by a judge on a higher standard of proof.
Mr Kennedy said the plans, like identity cards, showed that "whenever presented with a problem, the instinctive response of this government is authoritarian".
Opposition MPs are angry they only have two days - Wednesday and next Monday - to debate the plans.
In a rare move, the Tories and Lib Dems have jointly tabled a motion opposing the new bill, calling the house arrest plans "excessive".