WASHINGTON – Senator Schumer is taking aim at a proposed law backed by New York’s banking industry that would make it more difficult for people who declare bankruptcy to avoid paying their debts.

Mr. Schumer plans to offer an amendment to the “Bankruptcy Abuse Prevention and Consumer Protection Act” that the legislation’s supporters say could kill its chances of passing.

Mr. Schumer’s amendment targets a narrow issue in the wide-ranging bankruptcy overhaul bill, which spans more than 500 pages. The amendment would deny bankruptcy protection to anti-abortion activists who want to avoid paying court-ordered damages related to illegally blocking access to abortion clinics.

Mr. Schumer has called the tactic an abuse of the law and has introduced the amendment in the past, killing support for the bill among some Republicans.

“It’s a poison pill for the bill,” said Laura Fisher, a spokeswoman for the American Bankers Association. “If it gets attached, it could ruin the chances for the bill’s passage.”

Senate Republicans hope their strengthened majority will provide the necessary votes to pass the law, which the credit card and banking industries have sought for seven years.

But yesterday, as debate over the bill began on the Senate floor, Senator Hatch of Utah pleaded with his colleagues to refrain from introducing amendments.

“Any further amendments might scuttle this bill,” Mr. Hatch said.

The bill, which has been through multiple rounds of delicate negotiations, is needed to “eliminate some opportunities for abuse that exist in the current system,” Mr. Hatch said.

Mr. Schumer has not decided whether he will oppose the law if the amendment is not accepted, said his spokesman, Israel Klein.

New York’s senior senator was scheduled to hold a joint press conference today with an arch-critic of the bill, Senator Kennedy, a Democrat of Massachusetts.

Mr. Kennedy characterized the bill as having been written “by the credit card companies for the credit card companies,” and has said the law does nothing to protect people who are driven into bankruptcy by high medical bills.

The bill’s lead champion, Senator Grassley, an Iowa Republican and chairman of the Finance Committee, has said the criticism is unwarranted because the majority of people who file for bankruptcy report debts of less than $5,000.

The American Bankers Association has argued that the bill is necessary because bankruptcy protection increasingly is becoming an easy option – a “first stop” rather than a “last resort” – for many borrowers who can afford to meet at least some portion of their financial responsibilities.

Current laws are too lenient on debtors who have the means to pay their debts, and they raise the cost of credit to millions of responsible borrowers who pay their bills, the association has said.

But not all financial institutions agree. The senators will oppose the bill today at a press conference joined by the CEO of the Delaware-based online bank ING Direct, Arkadi Kuhlmann, and the president of North Carolina State Employee’s Credit Union.

Mr. Kuhlmann, whose company offers saving accounts and home loans, has said the bill would create “a form of debt imprisonment.” He has also expressed concern that the legislation will not protect consumers who have been victims of identity theft.

One of the bill’s most controversial provisions would require people above a certain income level who file for bankruptcy to enter into repayment plans under Chapter 13 of the bankruptcy code, rather than having their debts eliminated under Chapter 7. A debtor could only avoid repayment by demonstrating “special circumstances.”

The provision, referred to as the means test, would require people who earn more than their state’s median income and can afford to pay at least some of their debts using future earnings, to enter into repayment plans.

The bill makes other changes to the law, such as increasing the repayment priority of child support payments and alimony, and requiring people to undergo credit counseling before petitioning for bankruptcy protection.

Critics say the formula used to determine whether a person can afford to pay the debts is flawed for various reasons, including using past wages to determine future earnings. In cases of bankruptcy, a person may have lost their job or become ill or injured and incapable of earning their past wages, they say.

The Consumer’s Union, the non-profit publisher of Consumer Reports, has called the bill a “disaster” that does nothing to help people who go bankrupt due to medical problems.

But Mr. Hatch yesterday said the bill’s means test would not affect low-income people or deny anyone access to bankruptcy relief. He called the legislation “simple, fair, and long overdue.”