SEOUL, AUG. 28 -- The government launched a sweeping crackdown against its critics today, blocking rallies in several cities, rounding up scores of activists and intercepting the funeral procession of a shipyard worker killed in a labor dispute.

The day's activities, culminating in violent confrontations between police and several hundred students in a working-class suburb of Seoul, represented the government's greatest show of force since it promised democratic reforms two months ago. Coming after two months of relative liberalization, the new hard line seemed sparked by fears of cooperation in protests by radical students and labor activists that in the past has been used to justify military intervention in the political process.

But the day's activities also seemed to mark a failure, at least for now, of dissident leaders to align themselves with workers who have struck hundreds of companies recently. A leading dissident organization had called for a general strike and massive rallies to mark the death last Saturday of the first worker killed by police this summer, but police blocked the rallies and the strike never materialized.

Perhaps the most dramatic event of the day came when 2,000 police turned back a funeral procession from the Daewoo shipyard on Koje Island. Colleagues of the slain worker, 21-year-old Lee Suk Kyu, had planned to bury him in the provincial capital of Kwangju -- site of a bloody antigovernment uprising in 1980 -- against the wishes of Lee's family, but police in effect hijacked the hearse and led it to the family hometown of Namwon.

Workers had argued that Lee, who reportedly was killed by a police tear-gas grenade during a demonstration one week ago, should be buried near the victims of the 1980 revolt as befits a "hero of the working-class struggle." Family members had pleaded to have Lee buried in their smaller hometown.

The funeral had been delayed since Wednesday because of the debate, and it was delayed four more hours this morning as the wrangling continued. Finally, workers simply took the body and headed for Kwangju, prompting the family to boycott the funeral and sending Lee's mother to the hospital with what was described as exhaustion.

But police met the procession of 28 buses and cars in Gosong and forced all but two of them to return to Koje Island, where the Daewoo shipyard is located. The labor dispute that led to Lee's death was settled early this morning after 19 days, with workers and management agreeing on a raise of about $56 a month. Beginning workers now earn about $260 a month.

About 600 other strikes continued around the country, however. Since President Chun Doo Hwan acceded on July 1 to opposition demands for free elections and other reforms, more than 2,000 companies have experienced labor disputes.

In the past few days, the government has signaled a harder line against such disputes, claiming that "impure leftist elements" are to blame for many.

"An unflinching stern response to radical forces constitutes the precondition to true democratic development," Prime Minister Kim Chung Yul said.

Dissident groups have said that South Korea's repressive labor laws, which have essentially prohibited strikes and most national labor unions, have forced workers to seek assistance from outside. They also say that most strikes of the past two months have been spontaneous and leaderless, a response to the lifting of pressure after years of enforced low wages.

"The labor disputes are expressions of the workers who have been forced to sacrifice themselves in the course of the nation's economic development," opposition party spokesman Kim Tae Ryong said. "It is intolerable that the government responsible for the current situation refuses to apologize and instead threatens to take tough measures against the labor disputes."

Police authorities said they have taken 74 people into custody on charges of inciting labor disputes. Many are said to be university graduates who disguised their background to get factory jobs, a crime under South Korean law.

In addition, police said 1,618 "left-leaning" students and others are under investigation.

Earlier this week, the government arrested a key student leader for criticizing the government in interviews with The New York Times and The Financial Times of London, among others.

"I think they're trying to do the right thing, but they're not doing it very well," a conservative western diplomat said. "I think they've been trying to isolate the radical forces from the mainstream. . . They're trying to get at the core people, but I think they're misfiring."

About 5,000 police massed at Yongdongpo outside Seoul to prevent a rally tonight. The National Coalition for a Democratic Constitution, which organized the June rallies that helped bring the promise of reforms, had called for memorial meetings to honor Lee Suk Kyu.

But only a few hundred students gathered, and the massive show of force limited them to hit-and-run skirmishes. Students threw rocks and firebombs while police fired canisters of tear gas.

At least 140 students were arrested during the clash, police said.

Special correspondent Young Ho Lee contributed to this report.