The Liberal Democrats are urging people to renew their passports to avoid being entered on the National Identity Database for the next 10 years.
People can buy themselves '10 years freedom' from the database
People applying for a new passport will start having details - such as eye scans - taken and stored from 2008.
Nick Clegg was among five of the party's MPs who took their passports to Passport Office in Victoria, London, to highlight the option.
"You do not have to wait until your passport runs out," advises Mr Clegg.
The Identity Cards Act was introduced earlier this year, following a rocky passage through the House of Lords.
Once the National Identity Database is set up, everyone who applies for a passport will have to attend an interview, provide fingerprints and have their irises scanned.
But under the slogan "Renew for Freedom", campaigners from NO2ID are encouraging people to renew their passports this month, before the database is set up, in a bid to keep their details off it until 2016.
People can renew their passport at any time, but they will not be compensated for any unexpired time on their current passports.
However, they will save some fees by paying the current £51 charge for renewals instead of the minimum £93 the Home Office says passports will cost once the database is in operation.
Lib Dem home affairs spokesmen Mr Clegg, Lynne Featherstone and Mark Hunter were joined at the Passport Office by party president Simon Hughes and rural affairs spokesman Roger Williams.
Mr Clegg, whose own passport is not due for renewal until October 2012, said: "ID cards will be expensive, intrusive and ineffective.
"I urge everyone who is concerned about their introduction to join the NO2ID 'Renew for Freedom' campaign and renew their passport over the coming weeks.
"The Liberal Democrats were the only party to vote against the introduction of identity cards and we're making our opposition clear today by buying ourselves 10 years of freedom from this unnecessary scheme."
Although biometric details will be taken and stored from people renewing or getting passports from 2008, people will be able to opt out of having an ID card for two years.
From 2010 anyone renewing or getting a passport will have to get an ID card. The Conservatives also say they would scrap the identity card scheme if they win the next election.