New York City’s rate of HIV infection is about three times the national rate, according to estimates released Wednesday by the New York City Department of Health and Mental Hygiene.

The agency estimates that 72 of every 100,000 New Yorkers — a total of 4,800 individuals — contracted HIV in 2006, more than triple the national rate of 23 per 100,000.

HIV, or the human immunodeficiency virus, is the virus that causes AIDS.

In June, the city launched a three-year initiative to administer HIV tests to the 250,000 Bronx adults who have never been tested. The program was announced just days after release of a study finding a high rate of “unsafe sexual behavior” in the city.

Freidan said the study showed that 36 percent of gay and bisexual New York men who had five or more partners in the previous year did not use condoms consistently.

“This is a core group which is at high risk for getting and spreading HIV,” Freidan said.