WASHINGTON — Sen. Christopher Dodd, chairman of the Banking Committee, on Thursday warned credit card companies against jacking up interest rates before legislation takes effect that would limit their ability to do so.

In a letter to federal regulators, Dodd asked for help in enforcing the new rules and vowed to "closely monitor" bank compliance.

While not all card companies are guilty of abusive practices, "experience has shown we must maintain vigilant watch to protect the financial interests of the American people," he wrote.

Industry officials say a recent rise in credit card fees and rates is due to the bad economy and not related to the pending law.

The Credit Card Accountability Responsibility and Disclosure Act, which goes into effect in February 2010, requires banks to review any rate increases imposed after Jan. 1 and reduce the rate if the increase can no longer be justified.

Scott Talbott, senior vice president of government affairs for The Financial Services Roundtable, which represents the banking industry, said he didn't think the Jan. 1 provision would change much because lenders typically assess a person's risk every month and can justify their pricing.

The bill contains a separate provision that prohibits lenders from increasing a rate hike on existing balances unless a person is at least 60 days behind in paying the bill. If a person does fall behind and the rate on past buys is increased, lenders must restore the lower rate after six months if the cardholder has paid monthly bills on time.