Ministers have compromised on plans to introduce identity cards in an effort to head off a Commons defeat.
Peers defeated the government on ID cards last month
The government has accepted that completely new legislation will be needed to make the cards compulsory, following defeats in the Lords.
Home Secretary Charles Clarke said he had "listened to the concerns that people have expressed".
Government plans, opposed by Lib Dems, Conservatives and some Labour MPs, go before the Commons on Monday.
Mr Clarke told the BBC: "It is a concession because it's a different proposal than we originally had about the means of going compulsory.
"And it's designed to meet the concerns that some colleagues had but it's not a concession on the principle of going compulsory, which is at the core of the scheme."
The Identity Cards Bill was defeated three times in the Lords last month.
Peers voted the scheme could not go ahead until the full costs were known and for more security provisions for personal data stored.
The government has resisted pressure to reveal the full costs of setting up ID card schemes, saying it could jeopardise sensitive negotiations.
Under current plans, anybody getting a new British passport from 2008 would also get an ID card and have their biometric data, including fingerprints and iris scan, put on a national database.
But the Lords voted to ensure that entry on the register was only voluntary.
Shami Chakrabarti, director of human rights campaign group Liberty, said no compulsion was acceptable, including for those renewing passports.
"If this scheme is so great people should be able to choose and vote with their feet," she said.