If three men who died on Sunday are found to be the victims of hypothermia, they would represent this year’s first fatalities due to cold weather, a spokeswoman for the medical examiner’s office said yesterday.

On Sunday afternoon, police received a call that the frozen bodies of two men, ages 60 and 52, were found in a vacant lot at Calyer and Moultrie streets in Greenpoint, Brooklyn, law enforcement officials said. One man was found lying face up and the other was face down, police officials said.

Less than an hour later, a third body was found frozen in a park on Conduit Boulevard in Ozone Park, Queens. A passer-by noticed the body, buried under some snow and lying face down, police sources said. The dead man, identified as Lennox Hunte of Brooklyn, had a history of seizures and diabetes, police officials said. The 59-year-old was said to have been wearing a medic alert band on his wrist.

The cause of death in all three cases will not be determined until extensive tissue testing is done, the spokeswoman for the medical examiner’s office, Ellen Borakove, said. Test preparation is expected to commence today.

While police were able to identify the man found in Queens, it appears the Brooklyn men were homeless, officials said. According to news reports, the vacant lot was a gathering place for homeless people. Department of Homeless Services officials said it was not a site known to them.

That admission is “particularly troubling,” Patrick Markee, the senior policy analyst for Coalition for the Homeless, said. It makes on wonder how comprehensive the city’s outreach has been in that area, he said.

Outreach workers from the homeless services agency visited the Brooklyn scene yesterday to confirm whether an encampment had been set up in the lot and to see if there were any other homeless people requiring attention. The workers found no takers, agency officials said.

The deaths of the three men came on a frigid day when temperatures dipped below 20 degrees by nighttime, making it painful for anyone to be outdoors. The number of homeless people seek ing shelter was said to have increased that day.

The Brooklyn Drop-in Center, which can accommodate as many as 85 people, was bursting at the seams on Sunday, an employee said.

A Department of Homeless Services outreach provider, the Bowery Residents Committee, received 62 calls to its help line in a 24-hour period ending at 3 p.m. yesterday, compared with the usual 40 calls, its executive director, Muzzy Rosenblatt, said.

Mr. Rosenblatt said that while the cold spell certainly is an issue, it just exacerbates the everyday problems of homeless people, who often have serious medical ailments.

“In my mind, it’s not healthy to live on the street any day of the year,” Mr. Rosenblatt said.

While it is difficult to assess the number of fatalities among homeless people due to cold weather because not all bodies are identified at the time of death, the numbers spike during winter, Mr. Markee said. “It happens more often … than the general public thinks,” he said.

A 2005 survey by homeless services found that more than 4,000 people live on the streets of New York City, including inside the transit system. Of the five boroughs, Manhattan had the greatest share of the street homeless population living aboveground, with an estimated 1,805,according to the survey. Brooklyn had 592; the Bronx had 587; Queens had 335, and Staten Island had 231.The number of homeless people in the subway system citywide was estimated at 845, the survey said.

Even greater is the homeless population inside the city’s shelter system, which was 31,498, data from a January 12 daily report indicated.