As the number of complaints made against the police department reaches record levels, police officials are imposing harsh punishment on fewer officers, Civilian Complaint Review Board data shows.

The board received 6,796 complaints in 2005, an increase of 600 from the prior year, according to the board’s status report, released yesterday. The number of substantiated cases against police officers, however, dropped to 260 from 399 in 2004. Police and board members have consistently said the rising number of complaints is in part a product of citizens’ ability to make complaints through 311, a feature started by the city in March 2003.

Of the substantiated cases in 2005, the police department chose to let off 199 officers, or 59% of the cases, with a verbal warning or instructions. In 2004, the department let off 108 officers with a warning or instructions, or about 28% of the cases.

“The decline in the severity of penalties the NYPD imposes has only increased the already significant disparity between the disciplinary recommendations the CCRB makes and the actual discipline officers receive,” the report says.

A spokesman for the police department, Deputy Chief Michael Collins, said the change was attributed to a drop in the number of substantiated cases that required stronger punishment.

“The vast majority of cases are the type of case that should be handled at the precinct level,” he said.

The difference highlights a divide between Commissioner Raymond Kelly’s police department and the board, which broke away from the police department to become independent in 1993, experts said. “Frankly, in my mind, a little tension between the NYPD and CCRB is pretty healthy,” the president of the Citizen’s Crime Commission, Richard Aborn, said. “But it seems to me that the department needs to sit down with the CCRB and figure out why there is such a disparity.”

In recent months, this division has been characterized by strong language. In May, Mr. Kelly fired a letter back to the board’s chairman, Hector Gonzalez, after the board criticized two ranking police officials for their performance during the Republican National Convention in 2004. The board said two deputy chiefs didn’t properly use bullhorns to give protesters directions, resulting in unnecessary arrests.

Mr. Kelly called the letter “unprofessional,” and said the board was attacking the department without acknowledging the generally successful policing of the event. He also called the board’s efforts to let protest groups know about complaint procedures in advance of the convention an attempt to make it as easy as possible to bring in complaints against the department.

“Despite the board’s best efforts to facilitate complaints, only 63 were received. More remarkable, only three were substantiated,” he wrote. “Yet despite this insignificant complaint volume, the board has felt the need to generate substantial media interest in its recommendation that deputy chiefs should have been equipped with bullhorns.”

As well, the board reported yesterday that the number of abuse of power accusations has increased at an even faster rate than the number of complaints in general. Between 2001 and 2005, the number of allegations that a police officer improperly questioned or stopped a civilian has risen 462%. Chief Collins said only 78 cases were substantiated over the five years.

A professor of police science at John Jay College, Eugene O’Donnell, said the way the department doles out discipline to those found to have infringed on civilian rights is indicative of how the department views outside oversight – a source of tension for the department over the years. “Verbal warnings are as low as you can get,” he said. “You can’t be accused of blowing it off, but you’re basically blowing it off.”