''We're always looking at ways to make the UK passport more secure,'' a Home Office spokeswoman said. ''The idea is to supplement standard photographs with other biometrics that could be stored on a smart card.''
Biometrics are personal details such as fingerprints.
The cards would be used alongside paper passports, which would still be required to cross borders.
UK Passport Service chief executive Bernard Herdan said smart cards would make it easier for police to verify the identity of passport holders.
''This is about allowing people to assert their own identity and preventing fraud and stopping identity theft. This is not about 'Big Brother','' Herdan told Computing Magazine.
The Home Office said the smart card would not be introduced without government approval and public consultation.
The civil liberties watchdog Liberty said it was concerned about having intimate personal details recorded in a central database.
''We have no objection to making passports harder to fake, through digitising photos and so on, but the database takes it a very large step further,'' said spokesman Roger Bingham.
Britain is one of the few countries in Europe where citizens are not required to carry any form of identity when they leave their home.
Home Secretary David Blunkett said earlier this month that the government would consider introducing entitlement cards for all Britons.
The cards, which would carry personal information and biometrics, would be used to check a holder's right to receive health, education and welfare benefits.
The government has already introduced ''smart'' identity cards for all new asylum-seekers arriving in Britain. The controversial cards include the bearer's picture, name, birth date and nationality and a microchip containing other personal data.