CRANSTON — About 12,000 out-of-work Rhode Islanders will exhaust their unemployment benefits over the next several months unless Congress acts soon to extend existing benefit programs, according to state estimates.

Because of the way the law works now, many people who are scheduled to continue collecting benefits will run out in stages between January and June, said Raymond A. Filippone, assistant director of the Rhode Island Department of Labor and Training, who oversees unemployment programs.

The process will begin in early January, when about 1,000 out-of-work Rhode Islanders will start exhausting benefits each week, Filippone said.

That process will continue through mid-2010. The number of people exhausting benefits each week will decline as time goes on, he said.

But overall, about 12,000 out-of-work Rhode Islanders will run out of benefits over the next six months, Filippone said.

“That’s a sizable number,” Filippone said in an interview Monday at the agency’s headquarters in Cranston.

It is not clear whether Congress will act before leaving later this month for the holidays.

Sen. Jack Reed, D-R.I., last week introduced legislation to address the problem. The bill, cosponsored by Sen. Sheldon Whitehouse, D-R.I., and several others, would, among other things, extend unemployment benefits through 2010.

Antipoverty activist Henry Shelton said that Congress must act soon.

“I think it would be awful — it would be chaos — if they didn’t,” said Shelton, coordinator at the George A. Wiley Center, a community organizing center based in Pawtucket.

The unemployed need the benefits to help pay for basic living expenses, including food, utilities and housing, he said.

Rhode Island’s unemployment rate, at 12.9 percent, is the third-highest in the nation, behind Michigan (15.1 percent) and Nevada (13 percent), according to the U.S. Bureau of Labor Statistics.

About 35,000 out-of-work Rhode Islanders are currently collecting some type of unemployment benefit through the Department of Labor and Training, according to agency figures as of Dec. 2.

So far this year, the agency has distributed about $673 million in benefits, some of which have been paid for through a loan from the federal government.

The complex unemployment program generally works this way:

•People who are laid off typically begin collecting benefits for up to 26 weeks through the state unemployment program. (It is typically paid for through a state tax on employers. The average weekly benefit is $378.)

•Once the unemployed exhaust those benefits, they may be able to continue collecting through the federal emergency unemployment compensation program (known as EUC), which is divided into four levels: One covers up to 20 weeks, another up to 14 weeks, another up to 13 weeks, and another up to 6 weeks. (These benefits are typically paid by the federal government, through a federal tax on employers. The average weekly benefit is $372.)

•Once the unemployed work their way through the tiers of federal extended benefits, they may be eligible to collect state extended benefits, which are divided into two levels: the first for up to 13 weeks, the second for up to 7 weeks. (Half of this program is typically paid with state unemployment funds, the other half by the federal government. But for several months, the federal government has paid all of it. The average weekly benefit is $350.)

Under current law, starting in January, those who are collecting under the state’s basic 26-week program will not be able to move on to the federal EUC extended benefit program, Filippone said. (They might be eligible for state extended benefits, but only if they clear a number of eligibility hurdles.)

Also starting in January, those who are collecting federal extended benefits within a certain EUC tier will not be able to move on to the next tier (though some will move to state-extended benefits), Filippone said.

Because of these and other factors, about 1,000 Rhode Islanders each week will run out of benefits starting in early January, Filippone said.

And Rhode Island is not alone. The National Employment Law Project, a New York-based research and advocacy group, said on Monday that a million unemployed workers nationwide will run out of benefits in January unless Congress renews the unemployment benefit provisions that were contained in a federal law enacted in February. By March, that number will jump to more than 3.2 million workers, the group said.

Another provision, which generally helps the unemployed pay for employer-sponsored health insurance through the federal COBRA law, is also set to expire Dec. 31.

In addition, a federal program that pays the unemployed an additional $25 a week, on top of their regular unemployment benefits, will expire on Dec. 31. “That $25 has helped a number of individuals” pay for food, utilities and other daily living expenses, Filippone said.

ndowning@projo.com