WASHINGTON – Businesses offering short-term cash advances against borrowers’ paychecks charge fees equivalent to annual interest rates of 182 percent to 910 percent, a new survey by consumer groups shows.

The companies making the so-called “payday loans” are increasingly entering partnerships with out-of-state banks to skirt the law in the 19 states that prohibit such loans, including Maine, according to officials of the Consumer Federation of America and Public Interest Research Group.

“Predatory triple-digit payday loans threaten vulnerable consumers in this economic downturn,” Edmund Mierzwinski, consumer program director for PIRG, said at a news conference Tuesday. “We urge Congress and the states to ban … holding checks as ransom for fast loans.”

Disputing the groups’ statements, a representative of the booming payday loan industry said the product fills a market need, especially for consumers raising families who face unexpected financial emergencies.

“They’re making a reasoned decision. … They do need access to credit,” Lynn DeVault, a director of the Community Financial Services Association, said in a telephone interview. The trade group represents about half of the estimated 8,000 to 10,000 payday loan businesses around the country, many of them storefront shops.

A Georgetown University study commissioned by the group found payday loan customers have an average annual household income of around $33,000 and that some 36 percent own their home.

“Americans who have been ravaged by recession need more alternatives to get through these tough times, not fewer,” said Al Cors Jr., vice president for government affairs at the National Taxpayers Union. “The misguided assault on payday loans should end.”

Payday loans work this way: You need money today, but payday is a week or two away. You write a check dated for your payday and give it to the lender. You get your money, minus the interest fee. In two weeks, the lender cashes your check or charges you more interest to extend, or “roll over,” the loan for another two weeks, possibly at a higher interest rate.

The most common fee for a $100 cash advance is $15, an interest rate of 390 percent on an annual basis, according to the groups’ survey. The $15 fee was charged by 30 percent of the 235 payday loan stores surveyed in 20 states and the District of Columbia. Industry officials say that is reasonable compared with the fees banks charge for bouncing a check, which average nearly $22.

The survey found that 18 percent of the stores charged $20, or 520 percent annually, while 21 percent charged $17 or so, with annual rates between 442 percent and 459 percent. It found that only 32 percent of the lenders disclosed the annual rates on charts or brochures in their stores.

Critics say the loans, especially when rolled over, can trap consumers in a cycle of perpetual debt. The businesses target low- and moderate-income people, minorities, women who head families and military personnel in some parts of the country, according to the consumer groups’ research.