Workers' complaints about being denied overtime pay (search), wages and job leave guaranteed by law rose this year to the highest level in four years, the Labor Department said Wednesday. Penalties for violations and awards of back wages fell.

The department's Wage and Hour Division (search) received 31,786 worker complaints in the federal budget year that ended Sept. 30. That compared with 31,123 complaints in 2003.

The increase came as the department was putting in place overtime rules that Democrats warned would strip rights to premium pay for millions of workers. The Bush administration said that more than 100,000 workers, but not millions, could lose overtime pay rights.

Wage and Hour Administrator Al Robinson said a growing work force accounted for much of the increase in worker complaints about overtime pay, minimum wage, child labor and Family Medical Leave Act (search) violations.

The number of investigators in the division was down slightly in the past year, although the department could not immediately provide figures. Robinson said that had little effect on the decline in penalties and back wages.

"We're trying to be better and more efficient, and we are working more productively," he said. Robinson noted that the average time to resolve complaints fell to 92 days from 108 in 2003.

The division assessed nearly $9 million in civil penalties in the past year, compared with nearly $10 million in 2003. It collected $196.7 million in back wages, down from $212.5 million in 2003. Much of it involved overtime violations. The number of employees receiving back pay fell to 288,296 from 342,358 in 2003.

Employers pushed for this year's revisions to the Fair Labor Standards Act (search) to help slow the number of successful lawsuits by workers who claimed they illegally were denied overtime pay.

The impact of the new rules, which took effect in August, is difficult to measure. The Labor Department says employers are reporting that more employees have become newly eligible for overtime pay, and few have lost it.

Scattered incidents of overtime pay cuts have been reported in newspapers. Labor unions argue that employers did not implement the changes right away. Unions officials predict more workers will lose overtime now that the election is over, employers are up to speed on the rules and union workers are starting to negotiate new contracts.

"We remain very concerned about the change in overtime rules, which we think threaten overtime protections for millions of workers," said Chris Owens, policy director for the AFL-CIO (search). "We hope the department will be very vigilant in monitoring how the rule is being implemented by employers."

Among the department's largest overtime cases were T-Mobile USA, which agreed last year to pay $4.7 million in back wages to 20,546 call center workers; Phoenix-based World Super Services, which agreed this year to pay $1.4 million in back wages and penalties to settle overtime and minimum wage charges involving 3,143 workers that unloaded commercial trucks at warehouses across the country; and Siemens Building Technologies in Bellevue, Wash., which agreed to pay $1.2 million in overtime back wages to 52 employees.

Child labor violations also fell slightly in the past year, the department said. Complaints of Family Medical Leave Act violations dropped and fewer violations were discovered.