The Sandinista government, which is stepping up its war against U.S.-backed rebels, has begun hunting down draft dodgers and in at least two cases has triggered disturbances by young men and parents who oppose the draft, according to witnesses and a human rights official.

Nicaragua's first conscription law went into effect Oct. 6, 1983, but the government did not begin to pursue draft evaders in earnest until last summer. After at least two confrontations with townspeople, including one in which a man was killed, and with an election campaign just beginning, the Army stopped the roundups. It did not renew them until about one month after the Nov. 4 balloting in which the Sandinista candidate, Daniel Ortega, won the presidency.

The government insists that relatively few young men try to evade military service, but Catholic Church officials and opposition politicians say resistance is widespread.

According to residents of Nagarote, a town of about 16,000 people in cotton country 25 miles northwest of Managua, Army trucks sealed off roads leading out of town just before dawn Dec. 28. Directed by local Sandinista block committee officials -- whom some residents refer to derisively as spies, or "toads" -- soldiers entered houses thought to harbor draft evaders. Residents said soldiers detained any young man who appeared close to draft age, 17 to 23.

Residents said the soldiers were accompanied by packs of young Sandinista sympathizers in civilian dress, who are called turbas divinas, or "divine mobs." The residents said the soldiers and the youths carried billy clubs and sticks and that parents who tried to impede the roundup were beaten.

"The streets were full of mothers screaming and fighting with the soldiers. It was a terrible riot," said Danilo Corea, 41, a merchant who said he did not participate in the disturbance.

Then, according to Corea and other residents, some parents started ringing the church bells.

Several hundred persons, mostly women and many of them carrying sticks, marched on the church and, according to some residents, forced several soldiers guarding a truck to hand over some of the young men who had been rounded up. Residents said barricades of stones and tree limbs also appeared in the streets to keep trucks from leaving town with the young men. The disturbance quieted down before noon, the townspeople said, leaving several persons slightly injured. There reportedly were no shots fired during the disturbance.

Roberto Salgado, 35, a local Sandinista party official in Nagarote, said the disturbance was caused by "provocateurs," and that most residents do not oppose the draft law. Salgado said any young man grabbed in the roundup who was underage, overage or who had another legitimate excuse for not serving was released later.

An official of the Nicaraguan Permanent Human Rights Commission, an independent group, said that in another incident, on Dec. 22, draftees and parents who were visiting them at a boot camp, located at a military prison 10 miles south of Managua, staged a riot.

Lino Hernandez, chief of the legal department of the commission, said about 500 young men who recently had been rounded up broke through the gates at the facility called La Granja and most of them escaped. Hernandez said his information had come from participants and had been confirmed by an official at the camp. He said there were minor injuries, but no shots were fired.

Forced recruitment is traditional in Central American countries. Roundups in which young men are grabbed off buses, off the street or in movie theaters have been common in Honduras, El Salvador and Guatemala.

In Nicaragua, it is agreed that former dictator Anastasio Somoza treated members of his National Guard so well that it was not necessary for him to employ forced recruitment until his final year in power, when his Army was depleted by casualties and desertions. A nationwide draft is new to Nicaragua.

President Daniel Ortega said in an interview that draft resisters are a minority of the nation's youth and that the government does not consider the resistance a serious problem yet.

"It's inevitable," he said. "Some people will not like this kind of law, will not want to do their duty. In other countries, including the United States, governments have had the same problem."

Agustin Jarquin, president of the opposition Social Christian Party, agreed that the draft issue is not yet critical for the Sandinistas.

"But it is the kind of thing that can be used by people who want to create unrest," he said. "We're advising the government to try to resolve the problem."

Opposition leaders have suggested that the Sandinistas negotiate with the rebels, but the government has refused, insisting that the insurgents first lay down their arms.

The Army will not say how many young men have been drafted since the law went into effect, but in 1983 diplomats were estimating that the Army comprised 25,000 troops, and now the estimate is closer to 50,000.

There are also reservists and militiamen who have seen combat. The Army has not made public the number of young men who have refused to serve and are doing the six-month to two-year penalty in jail.

Some mothers interviewed said they considered any draft system immoral and were surprised to learn that other countries, including the United States, had draft laws. Nagarote residents say young men are hidden in the town and on outlying ranches.

There are rumors of an "underground railroad" to safety from the draft. Young men who can pay the price will be escorted through the mountains to Honduras, according to the rumors. A journalist was told of a case of a foreign diplomat who provided the son of friends with a fake passport to leave the country.

One Nagarote mother said that when she heard the Army entering the town Dec. 28, she took her 18-year-old son to the house of a friend on the outskirts of town to hide him. Later she was outside the church with the other angry mothers, where she said she was clubbed by a Sandinista supporter.

She said she did not want her son to go to the war. She said two young men who had been drafted last year had come home in coffins less than six weeks after they left town. In recent weeks Sandinista officials have used different figures for the number of troops killed last year, but it is believed to be between 1,000 and 2,000.

"They don't train them, they just send them into the mountains to die," the mother said.

She praised the Sandinistas for the health center, the preschool and the new telephone office they had built in Nagarote, but damned them for the draft.

"The Sandinistas are like a husband who kisses you one day and beats you the next," she said.