Protection from "abusive" credit card interest rate increases will go into effect Dec. 1, earlier than originally planned, under a bill passed by the House Wednesday at the urging of U.S. Rep. Barney Frank.

Frank, a Newton Democrat whose district includes Norton, Norfolk, Foxboro and Mansfield, said the earlier start-up date was needed because credit card companies are racing to impose what he called "abusive" retroactive increases on good customers to beat the original Feb. 22 effective date of a cardholder Bill of Rights.

A study by the Pew Charitable Trust found companies were increasing rates an average of 20 percent.

Several members of Congress spoke on the issue Wednesday, saying they have been contacted by constituents who say they were given exorbitant increases.

The original bill prevents companies from raising rates retroactively on existing balances if the consumer has been making payments on time. It also mandates a 45-day notice on regular rate increases. Frank called the retroactive rate increases on good customers outrageous.

"It's the single unfairest financial transaction I can think of that doesn't involve a pistol," he said during floor debate.

Frank mocked claims by credit card companies that their computers could not be ready for the bill by Dec. 1.

He said the companies apparently have "great" computer software for raising interest rates, but the software goes "berserk" when it comes to holding rates steady.

The congressman said many Republicans have joined Democrats in supporting the bill, but the GOP leadership has sided with the credit card companies instead of consumers.

Rep. Jeb Hensarling, R-Texas, opposed the bill, saying it will make credit more expensive and less available.

He also said senior citizens will have trouble getting credit just as they need it most to pay for the "trillion dollar government takeover of health care."

Banks and other credit card companies fought the bill.

Scott Talbott, a vice president with the Financial Services Roundtable, told the Associated Press the companies he represents are "struggling in a tough economy and trying to provide credit for consumers."

The reasons rates are going up or credit lines are decreasing are based on two factors: a change in behavior, including a missed or late payment or exceeding credit limits, and the economic times. "We're in a recession, so the general risk of nonpayment has increased across the board, so credit card companies are adjusting to that risk by increasing interest rates or decreasing credit lines, even if the customer has a perfect history," Talbott said. "A very small percentage may see an increase in their interest rate or a decrease in their line of credit."

The bill passed 331-92. U.S. Rep. James McGovern, D-Worcester, voted with the majority.