The population of a new 600-bed shelter for the homeless in Anacostia rose to 225 yesterday, with 172 of the new residents coming there from a downtown shelter operated by the Community for Creative Non-Violence, according to a spokesman for the D.C. Coalition for the Homeless, which operates the Anacostia facility.

CCNV members disputed that 172 of their residents had abandoned the facility at 425 Second Street NW, which the federal government has said it will close, in favor of the federally sponsored Anacostia building.

CCNV leader Mitch Snyder asserted that only a handful of the 600 men and women residents at Second Street had chosen to move to the Anacostia shelter.

"Their numbers here at the Anacostia shelter have risen, and meanwhile our numbers have gone up by three also," Snyder said, adding that the federal government will not have any place to put the Second Street residents if that building is closed.

C. McClain Haddow, chief of staff of the Department of Health and Human Services, said the federal government is not obligated to find housing for Second Street residents if the Anacostia shelter fills up. He said the federal commitment was to provide the $3.7 million grant the D.C. Coalition for the Homeless is using to operate the Anacostia shelter for men and a companion shelter for women on Florida Avenue NW.

"That is the maximum we will expend and beyond that it is the District's problem," he said. "I don't care if there are 100 extra people or 1,000 extra people, it is Mayor Marion Barry's problem."

Meanwhile, at a news conference held outside the Anacostia shelter yesterday, Snyder called on Barry to help resolve the situation by committing the city to provide assistance to the CCNV shelter. He also asked the mayor to appeal for help directly to President Reagan, who a year ago pledged to make Second Street "a model physical shelter."

"We are at an impasse," Snyder said. "Who can change the equation? If not Marion, who?"

Since August, the Barry administration has rebuffed federal efforts to involve the city in relocating the estimated 600 residents of the Second Street shelter. Snyder said yesterday, however, that Barry has never completely ruled out a city role in the shelter operation.

A spokesman for the mayor said Barry's position is that the shelter is a federal problem.

The federal government's timetable for closing the Second Street shelter remains in doubt. Federal officials have said they would wait a week to two months after the Anacostia shelter opened before closing the CCNV facility.