A network of left-leaning public-interest groups has come out in opposition to the Obama administration's new overtime rule, prompting charges of hypocrisy from progressives who back the rule.

U.S. PIRG, a coalition of state nonprofits around the U.S., issued a statement last week saying the new overtime regulations would hamstring its efforts to hold corporations accountable. The new overtime rule will expand overtime eligibility to millions of workers who currently don't qualify.

"Organizations like ours rely on small donations from individuals to pay the bills. We can’t expect those individuals to double the amount they donate," the group said in its statement. "Rather, to cover higher staffing costs forced upon us under the rule, we will be forced to hire fewer staff and limit the hours those staff can work – all while the well-funded special interests that we're up against will simply spend more" (emphasis theirs).

The share of salaried workers eligible for overtime pay is a fraction of what it used to be in the U.S. By updating the rules to make them more generous to workers, the Obama administration will be giving employers a tough choice: Either limit the workers' hours to 40 per week, or pay them time-and-a-half for any extra hours they work.

Corporate America has predictably blasted the rule as a job killer, enlisting Congressional Republicans to block it. U.S. PIRG's opposition is a reminder that even some otherwise progressive groups may not like it either, since it will raise their payroll costs or compel them to work their employees less.

Overtime is probably one of the few issues where U.S. PIRG finds itself on the same side as House Speaker Paul Ryan (R-Wis.). In fact, Ryan singled out groups like U.S. PIRG when he spoke against the rule, saying it will hurt nonprofits.

The White House will be expanding the number of workers eligible for overtime by raising the so-called salary threshold -- the number below which all salaried workers are entitled to overtime pay, regardless of their job duties. The current threshold is just $23,660 per year. The new one will be $47,500.

U.S. PIRG's strong opposition to the rule suggests it may have many staffers who earn less than $47,500 a year but regularly work more than 40 hours in a week.

Andre Delattre, the group's executive director, told The Huffington Post that U.S. PIRG supports "the intent of the rule," but that the regulations should distinguish between for-profit companies and non-profit groups. Someone working at McDonald's to draw a paycheck, Delattre said, is not the same as someone doing "mission-driven" work.

"I think most people understand that there is a difference between the people this rule is trying to protect and other people who are doing work that they're choosing to do," Delattre said.

People on Twitter have hammered U.S. PIRG for opposing a regulation lauded by low-wage worker groups and labor unions.

Amazing that @uspirg would argue that keeping their workers poor is OK because they serve the 'public interest'.https://t.co/15RSh52N4y — Mark Elliott (@markmobility) May 22, 2016

.@lydiadepillis @uspirg should be ashamed. They have opposed living wages for their own employees for far too long. #RaiseTheWage — Eric Robertson (@erictheteamster) May 22, 2016

.@uspirg IT'S LITERALLY DISGUSTING THAT YOU EXPECT PEOPLE TO WORK 80+ HOURS A WEEK FOR $24,000 A YEAR.



YOU SHOULD BE ASHAMED — Misandry (@OHTheMaryD) May 21, 2016

Reading the @uspirg’s mentions right now is brutal. I hope their twitter manager is getting that #overtime. — Andrew Nazdin (@andrewnazdin) May 22, 2016

U.S. PIRG was founded by consumer advocate Ralph Nader. (A representative for Nader, who doesn't appear to be affiliated with the group anymore, didn't immediately respond to a request for comment.) According to its mission page, the group "stands up to powerful special interests on behalf of the American public, working to win concrete results for our health and our well-being." Its campaigns include combatting money in politics, exposing banking fees and limiting the use of antibiotics, among other causes.