The years-long battle over one of D.C. Police Chief Cathy L. Lanier’s banner initiatives — in which she blankets the city with officers several times a year — has heated up again, with millions of city dollars and the future of the strategy potentially on the line.

A Friday ruling has ordered police to pay hundreds of officers retroactive overtime. The labor union, meanwhile, says the All Hands on Deck initiative, unpopular with some officers, has been declared dead. But the city disagrees, and Lanier plans to proceed with another deployment scheduled for this weekend.

The appeals ruling, by the city’s Public Employee Relations Board, says at a minimum, Lanier did not have the authority to change officers’ schedules to have them work weekends four times in 2009. The cost of that misstep has not yet been determined but is estimated in the millions.

Lanier says the ruling, which upholds a 2009 decision, only holds her agency responsible for a blunder that temporarily took away some of her personnel authority — and which has since been fixed.

“It was an oversight,” Lanier said. “As soon as we realized it, it was corrected.”

Lanier said she is talking with the attorney general’s office to determine whether to appeal the decision. She attributed the problem to a 2009 gaffe made by then-Mayor Adrian M. Fenty’s administration that, in consolidating personnel power across the city, took away her authority to alter officers’ schedules.

But the ruling also says All Hands on Deck is illegal, according to Kristopher Baumann, Fraternal Order of Police chairman. Lanier never had the authority to change officers’ schedules because that would violate their contracts, Baumann said.

A message left at the Public Employee Relations Board was not returned Monday.

“Since the arbitrator’s ruling in September 2009, Chief Lanier has wrongfully continued scheduling AHOD deployments, without regard to police officers’ rights and the District’s growing debt for unpaid overtime that she is creating,” Baumann said in a news release.

He also has accused Lanier of using the strategy as a publicity gimmick.

“What the FOP would prefer is that the Department actually follow the law and devise long-term crime fighting strategies, rather than public relations stunts that, among other things, pull detectives and other personnel from their cases in order to write parking tickets,” he said in an e-mail.

D.C. Council member Phil Mendelson (D-At Large), head of the Public Safety and Judiciary Committee, said the ruling is unclear about whether Lanier would be in violation for future initiatives. He said the strategy helps reduce violence and other crimes across the city.

“The decision doesn’t say All Hands on Deck is improper, just that what happened in 2009 was improper,” he said. “Presumably, it’s been fixed.”

Lanier defended the program, saying it aims to get ahead of crime. During the most recent deployment, from July 22 to 24, crime was down 24 percent compared with the same days in 2010, according to the department.

“I don’t think the people of the District of Columbia want me to wait until there’s a spike in murders and other crime,” Lanier said.

Her predecessor, Charles Ramsey, called a crime emergency in response to an increase in violence in 2006, which forced officers to work 12-hour days six days a week. That cost the city $17 million, according to Lanier.

In contrast, All Hands on Deck is not supposed to require overtime because it uses a prearranged schedule that allows for days off.

“I’m making them to do it four times a year. I don’t think I’m asking that much of a sacrifice,” Lanier said. “Our core mission is to prevent crime and make the whole city safe. Nobody told anybody when they came here they wouldn’t work evenings and weekends.”

But Baumann has said All Hands on Deck is counterproductive.

“AHOD deployments and the Department’s blatant disregard for the law have caused serious morale problems that have contributed to the dangerous decline in police staffing,” Baumann said in his news release. “District residents deserve better.”

Staff writer Mike DeBonis contributed to this report.