DENVER - Prosecutors may soon have a new tool to use in their fight against Internet fraud. But whether that tool will be useful — or even used at all — is a matter of debate.

The House Judiciary Committee gave its unanimous support Wednesday to a bill that would toughen Colorado’s laws against spam. The measure would allow the attorney general’s office to prosecute people who use false e-mail addresses to commit fraud under the Colo- rado Consumer Protection Act.

House Bill 1178 is modeled on the federal Controlling the Assault of Non-Solicited Pornography and Marketing Act, which passed in 2003. Rep. Morgan Carroll, D-Aurora, said that her bill would allow the state to prosecute cases federal authorities have passed over, and that it restores powers the state lost when the CAN-SPAM Act superseded state law.

Four years after the CANSPAM Act was passed, experts believe 60 billion to 150 billion junk e-mails are generated daily.

Under Carroll’s bill, e-mailers who send consumers fraudulent messages claiming to be from banks or credit card companies would be targets under the law.

Testifying in support of the bill was Peggi O’Keefe, who represented Microsoft. She praised Carroll for reaching out to Internet service providers to make sure they supported and understood the bill. They would not be held liable for messages sent over their networks, and Carroll said companies and advocacy groups that make use of large e-mail lists would not be affected.

The bill claims jurisdiction over any fraudulent e-mail sent to a computer in Colorado.

The attorney general’s office would have wide latitude to determine how it would enforce the law. While it is possible the office could decide to crack down on spammers, the bill does not direct the office to dedicate staff to enforcing it, and it does not provide funding for more staffers.

Carroll conceded that prosecutors have not used earlier anti-spam measures.

“The past enforcement has been none; I hope in the future there will be more. It varies because it’s discretionary,” Carroll said.