The government is warning consumers to be wary of unofficial "cash for clunkers" Websites that seek personal information or direct consumers to pre-register for the program.

The National Highway Traffic Safety Administration says dealers and consumers do not need to pre-register for the program, which provides $3,500 to $4,500 to people who trade in gas-guzzling clunkers for a new vehicle.

Traffic safety spokesman Rae Tyson says the government has an official site for the program.

Tyson says some Websites have offered pre-approval sections that request a consumer's Social Security number and other personal information.

The traffic safety administration has given information about these unofficial sites to the Justice Department's Internet Fraud division.