In the two years he has been in this country, Cuban emigre Gerardo Font Martinez says he has been unable to find more than occasional work.

But he has lived, for at least part of the time, with the help of $190 a month in federal refugee aid. Now Martinez has lost that because the Reagan administration reduced the period of refugee assistance from 36 to 18 months.

Martinez, 41, who informally shares a Northwest apartment with several other Cubans, studies English at the Andromeda Hispano Mental Health Center in hope of improving his chances of finding a job. As a single adult with neither dependents nor special handicaps, Martinez cannot qualify for other aid programs. He is ineligible for food stamps because he has no permanent address.

The reduction in refugee aid, which took place April 1, affected about 160 District cases, leaving 237 cases representing 307 people. These cases include Indochinese, Ethiopians, Afghans and others. Not included are Cubans and Haitians for whom figures were not available.

The D.C. residents are among 112,000 refugees nationwide, including 38,000 Cubans and Haitians, who lost benefits because they had been in the country more than 18 months. The Refugee Act of 1980 provides both cash and medical assistance. Before the cutoff, an estimated 309,000 people nationally were receiving refugee aid.

The aid reduction is highly controversial, with Reagan administration officials saying the new policy will prevent long-term dependency and will provide assistance to refugees on the same basis as nonrefugees.

Hang Nguyen, director of Catholic Charities' Refugee Resettlement Program, said that in the case of Indochinese refugees, 18 months has been long enough for most to find jobs, but she added that state and federal assistance should continue to be available to those who need it.

However, single persons would be ineligible for such aid, Nguyen said. "We here are very willing to help them to find jobs," she said.

Lydia M. Fanfan, state coordinator for the D.C. Office of Refugee Resettlement, said she expected the impact of the aid cutoff to be severe, especially among single Cuban and Haitian men, who reportedly comprise 95 percent of the countries' immigrants.

"In some cases, there is very little that can be done," she said. "It's going to be a desperate situation, and I don't know what we can do to stave it off."

Fanfan said her agency had been helping find jobs for some newcomers and had most of its success with Indochinese and Ethiopians. Fanfan said jobs recently were found for 230 out of 503 persons.

The District originally took sharp cuts in its refugee monies, with the overall fund slashed from $610,500 last year to $164,000 for this year and its Cuban and Haitian Entrants Fund reduced from $194,000 to $24,000, she said.

But last week, the U.S. Office of Refugee Resettlement said it would give the District $155,000 more, so that the overall fund will not be cut by more than 50 percent, she said.

Fanfan said some affected persons will be eligible for food stamps, provided they meet income guidelines. They also can apply for welfare and other assistance programs.

Joan Reeves, an information officer for the D.C. Department of Human Services, said that after receiving word of the cutoff, the agency reviewed each case to determine if recipients were eligible for inclusion in other aid programs.

Jim Shenk, who works with Cuban entrants at the Andromeda Hispano Mental Health Center here, said there are many people like Martinez who are unable to find work because of the economy, lack of fluency in English and the "stigma" of being Cuban refugees.

Some Cuban immigrants are perplexed because in Cuba jobs, food, clothing and medical attention were all arranged for them, he said.

Martinez, telling his story through Shenk, recalled that he had left school at an early age to help support his mother, who was separated from his father.

In Cuba, he worked on construction projects, repaired boats and painted houses. He also worked on the docks before he injured his left hand when a freezer he was unloading fell on it, severing a tendon. He underwent an operation to give him an artificial tendon but has been unable to make a fist or to grip things.

Since coming to this country, Martinez has been an orderly at St. Elizabeths Hospital, a dishwasher and a house painter. He applied for Supplemental Security Income assistance (SSI)--available to people with handicaps--but was told he probably will not be eligible because he can find work where he needs only one good hand.

As it is, when Martinez finds work as a painter, he hides his injury from the employer and manages with one arm.