Complaints and arrests for corruption have risen steeply in the past five years, according to a Department of Investigation report that will be released today.

Complaints of corruption are up 46%, while arrests rose 35% since 2002, the report said. Investigators yesterday attributed the trend to new outreach efforts, not an increase in corruption itself.

“This year I beefed up the number of prevention outreach efforts,” the commissioner of the Department of Investigation, Rose Gill Hearn, said.

“It’s the second year of the second term,” she added referring to Mayor Bloomberg’s tenure in office. “I don’t want there to be any lull or any complacency. I don’t want people to get comfortable.” Ms. Hearn said the increase in arrests and complaints can also be attributed to her efforts to extend investigations beyond city officials to private contractors and others who participate in bribery and other corruption schemes.

“The only way to cut off the bribery is to cut off the supply of bribes,” she said.

Of the 368 arrests last year, 287 suspects were not employed by the city. Arrests were up 7% since last year, when 345 people were arrested.

Ms. Hearn said she created a task force this year to focus solely on nonprofit agencies that receive city grants following a two-year investigation into corruption at the Gloria Wise Boys & Girls Club in the Bronx. The task force is working on several cases of suspected corruption among nongovernmental organizations.

The end of several high-profile cases against elected officials, including Assemblyman Brian McLaughlin, a Democrat of Flushing, also contributed to the uptick in arrests, Ms. Hearn said.