Labor Secretary Elaine Chao (search) worked in public and private Monday to head off an embarrassing defeat in the Senate at the hands of Democrats challenging new Bush administration overtime regulations.

Speaking to nursing students in Florida, Chao said the regulation "makes clear that registered nurses who currently receive overtime will continue to receive overtime when the new rule takes effect."

Her claim drew a prompt rebuttal from the leaders of several nurses' unions. "For the first time in the history of the Fair Labor Standards Act (search) (FLSA), hourly paid employees, including registered nurses, may be denied overtime compensation," the Coalition to Preserve Overtime Rights for Registered Nurses (search) wrote members of the Senate.

With a close vote expected Tuesday, Chao arranged a private meeting with Sen. Lincoln Chafee (search) of Rhode Island, who has yet to take a position on the regulations. Chafee was one of six Republicans who sided with Democrats last fall in a 54-46 vote to scuttle an earlier draft.

The rules have been revised extensively since then, in part to meet the election-year concerns of Republicans who feared the impact among voters, particularly in a time of economic uncertainty.

The AFL-CIO (search) strongly opposes the regulation, arguing the change could cost millions of workers their overtime, and congressional Democrats have vowed to try and blunt its impact.

A proposal by Sen. Tom Harkin, D-Iowa, would block implementation of any portion of the regulation that strips workers of their current overtime eligibility.

The revised regulation includes declarations that police, firefighters and other "first responders" earning up to $100,000 a year will be eligible for overtime. Other provisions guarantee overtime to white collar workers who earn less than $23,660, and ensure that workers covered by union contracts are not affected by the regulations. The rules also say that veterans will not lose eligibility on the basis of military education or training.

In general, the Labor Department has said that only white collar workers earning more than $100,000 annually will be at risk for the loss of overtime pay (search).

The registered nurses are not the only ones worried about the regulation's impact. Workers in the computer, financial service and other industries, as well as a relatively small number of police also are uneasy.

While Labor Department officials have said repeatedly that police overtime will be protected - and the Fraternal Order of Police (search) has endorsed the revised rules - three unions said in a letter made public Monday that the impact on sergeants was unclear.

"Once the final complex rules go into effect, their very ambiguity regarding the line between supervisory duties and traditional policing duties will undoubtedly shift the battle from the legislature to the courts," wrote officials from the International Union of Police Associations (search), the National Association of Police Officers, and the International Brotherhood of Police Officers.

In a rebuttal, the Labor Department cited the preamble to the regulation, which says sergeants are "entitled to overtime pay even if they direct the work of other police officers because their primary duty is not management."