As more people struggle under credit-card debt, banks are stepping in -- to intensify their collection efforts.

Citigroup Inc. has hired more collectors, increased the frequency of calls to delinquent customers and expanded programs that let borrowers temporarily postpone payments or settle debt for less than the borrowers owe.

American Express Co. is giving some hard-pressed customers a break on their interest rate, fees or monthly payments. Bank of America Corp., meanwhile, is contacting late-paying customers earlier than it has in the past.

"We are doing a lot more collection work than we ever have, putting a lot more people on the issue than we have before," Bank of America's chief executive, Ken Lewis, said in the company's second-quarter conference call.

The increased attention means that even consumers who have forgotten just one payment could get a call from the bank. "Rather than have a letter go out in 15 days, they might send it out in five," says Robert Hammer, an industry consultant who runs a bank-card advisory firm in Thousand Oaks, Calif. "There is definitely a sense of urgency in the collections effort."

The moves come at a time when rising unemployment and a credit crunch are forcing more consumers to default on their credit-card payments. The percentage of bank credit-card accounts that are delinquent rose to 4.51% in the first quarter -- the latest available -- from 4.41% in the year-earlier quarter, according to the American Bankers Association. Banks reported increases in delinquency rates in their second-quarter earnings reports, and they expect the problems to get worse. One sign of the debt to be reckoned with: On Monday, the Federal Reserve reported that revolving debt -- primarily reflecting the balances on people's credit cards -- rose in July at a seasonally adjusted annual rate of 4.8% to $969.9 billion. That was faster than the 3.5% rise in June.

For their part, banks are under tremendous pressure to shore up their balance sheets amid an onslaught of bad loans and mortgages. Financial institutions are responding by working past-due accounts more aggressively. They are putting their best collectors on their toughest-to-collect accounts (those that are at least 60 or 90 days past due), hiring outsourcing firms to supplement their internal efforts and putting new hires on accounts that are in the early stages of delinquencies, says Mr. Hammer.

Some banks are using incentives to try to entice customers to pay them back. Citibank is contacting some borrowers with big balances with an offer to match a percentage of the payments they make over the minimum amounts due -- typically up to $550 -- if they agree to pay off a chunk of their balance over several months. The match is delivered as a credit to the account a few months after the offer period ends. In exchange, cardholders usually have to temporarily stop using their cards, and the bank could lower the borrowers' credit lines once they get their statement credit.

In July, D. Lavigne of Cincinnati got such an offer on one of his Citibank cards where he was carrying a balance close to the card's $10,000 credit limit. The information-technology consultant plans to pay off the entire balance over the next two months. "I think it's just Citi trying to shore up their books with all of the writedowns the company has had over the last few months," says the 31-year-old. A Citigroup spokesman declined to comment on a specific customer's situation.

Given the economic environment, companies are paying closer attention to any change in borrowers' payment and spending patterns. Borrowers who used to pay their bills early or who used to pay more than the minimum amounts due are likely to catch banks' attention if they suddenly start paying their bills exactly on the due dates and make only the minimum payments, says Tom LaMagna, director at Auriemma Consulting Group, a consulting firm that specializes in payments and lending in Westbury, N.Y. Such customers might get put on a watch list or get fewer credit-card solicitations, industry consultants say.

Companies are also turning to new tools to get delinquent borrowers to settle their debts. Last year, for example, Washington Mutual Inc. started directing borrowers who were several months late with payments to a self-service Web site where they could make a payment or set up a payment plan. "It lets them avoid the phone call," says spokesman Keith Givens. "It's a very confidential service." Online Resources Corp., which runs online-banking services, recently launched a "Virtual Collection Agent" that is now being rolled out by three of the top 10 card issuers. Meanwhile, credit bureau Experian Group Ltd. is marketing a program called "Collection Triggers" to creditors and collection agencies. The program, which mines Experian's credit data on borrowers, will notify debt collectors if it finds signs that a debtor's ability to pay is improving, such as a job change or any paid-down debts.

Indeed, companies have had to find new ways of reaching borrowers, who can increasingly avoid calls with answering machines and caller ID or who use cellphones as their primary phones, says Mr. LaMagna. One tactic they're using to get borrowers to call back: Mailing phone and gift cards that can usually be activated only if they call the company, he says.