Illegal file-sharers could be booted off the internet by summer 2011, says Lord Mandelson.
The Business Secretary, who has been charged with ironing out the UK's plans to tackle internet piracy, revealed that disconnecting repeat offenders will be a last resort.
Mandelson told the government's Digital Creative Industries Conference that the "consequence-free" days of illegal file-sharing are over, and that a "legislate and enforce" strategy had been identified as the best way to tackle the problem.
"Three strikes is a reasonable way of describing our approach," he said.
The legislation, which will see those caught illegally downloading sent warning letters, will be officially set out in the Digital Economy Bill that is expected next month and will come into force in April 2010.
"Technical measures will be a last resort and I have no expectation of mass suspensions resulting."
Repeat offenders will be issued with a second letter. If this fails to stop them illegally downloading, they will be put on a "serious infringers list", with ISPs expected to "exercise technical measures".
Mandelson also said that Ofcom will monitor the success of the warning letters in the first year and if illegal file-sharing has not reduced by 70 percent then suspending net connections will be brought into force.
"The threat for persistent individuals is, and has to be, real, or no effective deterrent to breaking the law will be in place," he added.
Mandelson also said a "proper route of appeal" would be available for those suspended from the web. Once notified of possible suspension, offenders will be given 20 working days to appeal to an independent body, although Ofcom has yet to appoint the body. Mandelson said the suspension would not come into force until the appeal has been heard.
He also said ISPs and rights-holders will "share the costs, on the basis of a flat fee that will allow both sides to budget and plan".