City agencies across the country are being overwhelmed by a growing tide of "newly poor" residents and jobless workers seeking emergency services, according to a survey of 55 cities released yesterday.

Officials from these cities said the double blow of federal budget cuts and the recession has left them unable to meet even half the need for emergency services such as food and shelter. They also said they are meeting only a fraction of the demand for health care, job training and programs for the aged.

Two-thirds of the cities, which were surveyed this month by the U.S. Conference of Mayors, said the Reagan administration's switch to block grants has hurt their social service programs. More than half said they had to dip into local funds to compensate for the federal cutbacks, while 60 percent reported increased contributions from private companies.

The survey report sought to dramatize the plight of those it describes as the "new poor" -- formerly employed people now sleeping under bridges in Tulsa, Okla., living in their cars on Houston freeways, losing their homes in Gary, Ind., or turning to alcoholism and violent behavior in Evanston, Ill.

Frank Benest, director of human services in Gardena, Calif., said the southwest and west are seeing "an influx of transient workers who have always been able to pay the mortgage and never considered themselves poor. They aren't finding jobs and they get desperate and show up at our door. We've just about run out of food."

Benest said that local businesses had raised $15,000 to rescue briefly an $80,000 day care program for frail elderly patients, but that it would soon be closed anyway because of federal budget cuts. "Businesses are faced by a recession at the very time we're asking them to fill an incredible funding gap," he said.

The report also described the effect of cutbacks on the "working poor," such as a working mother in Seattle who had to return to the welfare rolls when she could no longer receive day care for her children.

Minnie Nelson, director of Gary's social services agency, was among the 70 percent of local officials to complain that the states are ignoring their needs in handing out federal block grants. "We have no say-so in the state legislature," she said. "We can't even comment."

Nelson said Gary had to shut down a $100,000 training program for former prisoners because the state sent the block-grant money elsewhere. She added that her own division is being abolished after Christmas and nine of the 11 staffers will be laid off.

"State agencies were left intact, while the cutbacks were passed on to the people who provide the services," agreed Isabella Hinds of Cambridge, Mass., which has lost partial funding for day care and drug-abuse clinics.

In Baltimore, the mayor's office started a "Blue Chip-In" program after federal cutbacks reduced the number of summer jobs from 17,500 to 5,000. Local businesses, churches and community groups came up with $2.2 million, or enough for another 1,741 summer jobs.

Steven Kaiser, a spokesman for the mayor's manpower office, said other contributions under the program have helped provide work for those laid off from federally funded jobs. In one case, a local firm provided $30,000 for eight unemployed youths to turn an abandoned convent into a shelter for homeless women; in another, IBM Corp. volunteered to train 80 people in word processing.

"It's certainly good that we're getting the corporate community involved in training the unemployed," Kaiser said, "but it isn't enough to fill the gap."