President Bush signed a bill Wednesday that will make it harder for debt-ridden people to wipe clean their financial slates by declaring bankruptcy.

The legislation was strongly opposed by consumer rights activists who said it would prevent vulnerable Americans from getting the fresh start they need. But Mr. Bush said the law was “restoring integrity to the bankruptcy process.”

“Bankruptcy should always be a last resort in our legal system,” he said. “If someone does not pay his or her debts, the rest of society ends up paying them.”

Many people in debt will have to work out repayment plans instead of having their obligations erased in bankruptcy court, according to the law, which takes effect in six months.

People with incomes above their state’s median income will have to pay some or all of their credit-card charges, medical bills and other obligations under a court-ordered bankruptcy plan.

“This practical reform will help ensure that debtors make a good-faith effort to repay as much as they can afford,” Mr. Bush said. “This new law will help make credit more affordable because when bankruptcy is less common, credit can be extended to more people at better rates.”

Those who fought against the legislation said the change will hurt low-income working people, single mothers, minorities, and the elderly and will remove a safety net for people who have lost their jobs or face major medical bills.

“The big winners under the new law will be the special interests that literally wrote it, particularly the credit card industry,” said the legislative director of the Consumer Federation of America, Travis B. Plunkett. “This is particularly ironic because reckless and abusive lending practices by credit card companies have driven many Americans to the brink of bankruptcy.”

The financial services industry made the case that bankruptcy frequently is the last refuge of gamblers, impulsive shoppers, divorced or separated fathers avoiding child support, and multimillionaires who buy mansions in states with liberal exemptions to shelter assets from creditors.

Mallory Duncan, senior vice president and general counsel of the National Retail Federation, said bankruptcy filings have increased nine fold since 1978, when bankruptcy laws were last updated.

“Bankruptcy has gone from a stigma to a financial planning tool for many,” Mr. Duncan said.

New personal bankruptcy filings went from 1,613,097 in the year ending June 30, 2003, to 1,599,986 in the year ending last June 30, counter to that upward trend of recent years.

Between 30,000 and 210,000 people – from about 4 percent to 20 percent of those who dissolve their debts in bankruptcy each year in exchange for forfeiting some assets – will be disqualified from doing so under the law, according to the American Bankruptcy Institute.

Under the current system, a federal bankruptcy judge determines whether individuals must repay some or all of their debt.

Under the new law, people with insufficient assets or income could still file a Chapter 7 bankruptcy, which, if approved by a judge, erases debts entirely after certain assets are forfeited. Those with income above their state’s median income who can pay at least $6,000 over five years – $100 a month – would be forced into Chapter 13, where a judge would then order a repayment plan.

Those people have six months until the law takes effect to escape the tougher guidelines. Bankruptcy lawyers have said they anticipate a rush to the courthouse.