SEOUL, AUG. 25 -- Police arrested key student activists today for the first time since the government promised democratic reforms eight weeks ago, and dissident leaders threatened to call a nationwide general strike to protest the death of a demonstrating worker.

The apparent hardening of positions came amid growing labor unrest and swirling rumors of hard-liners' unhappiness with the rapid pace of change.

Ruling party chairman Roh Tae Woo, who unleashed the new freedom with his June 29 promise of direct elections and other reforms, acknowledged that some top officials have become "skeptical" about the prospects for democracy but insisted that the military will not intervene.

Officials arrested a student leader in Seoul on charges of leading illegal demonstrations. They said that Woo Sang Ho, chairman of the Yonsei University student council, also slandered the state when he criticized the current regime in interviews with the New York Times and elsewhere.

Police also arrested five former students expelled earlier from Yonsei for political activities, and charged them with inciting labor disputes.

The crackdown seemed likely to inflame activist students who are scheduled to return from summer vacations next week and who already had expressed impatience with what they view as the slow pace of democratization.

The escalating tension came as the nation registered its 2,000th labor dispute of the year, eight times as many as occurred during all of last year. One thousand strikes have broken out in the last month alone, and more than 600 remained unresolved today, government officials said.

The body of the first victim of that labor unrest, a young shipyard worker killed by a police tear-gas grenade Saturday, remained in a mortuary near the Daewoo shipyard today as dissident leaders wrangled about how to conduct his funeral.

Lee Suk Kyu, 21, was killed when locked-out shipyard workers clashed with riot police outside the giant Daewoo shipyard on the southern island of Koje. Workers in the yard, which employs 15,000 people, had been demonstrating for two weeks for higher pay.

The worker's family today pleaded for a simple burial in his home town, but union officials said they want a more rousing ceremony in the provincial capital of Kwangju. The leading dissident organization in Seoul, meanwhile, called for a massive rally and burial in the capital, with a general strike to take place on the funeral day.

"The mother keeps saying she wants him next to her where she can visit him," said a key union official, who asked to be identified only by his last name, Park. "We keep telling her, 'You're only going to live 30 more years, maximum. We want to put him where people can visit him and make him a national hero who will be remembered forever.' "

At the same time, the union resisted efforts by the National Coalition for a Democratic Constitution to take charge of the funeral and bury Lee in Seoul.

But dissident leaders in Seoul said they believe Lee Suk Kyu should become as much a rallying cry as Lee Han Yol, a student killed by a police tear-gas canister earlier this summer. His funeral became a rally for democracy that attracted hundreds of thousands of people.

So far, students and religious leaders do not seem to have succeeded in joining cause with striking workers, whose goals have centered on higher wages and more democratic unions. Such a joint struggle has long been one of the deepest fears of the authoritarian government here, however.

In recent days officials have warned with increasing shrillness about the danger of "impure elements" inciting workers, thereby threatening South Korea's remarkably successful export economy.

The arrest of the former Yonsei students today seemed a warning to activists not to pursue the relationshop with labor this fall. The five were accused of helping organize rallies at a Gold Star electronic plant in Pyongtaek, 60 miles south of Seoul.

South Korean law prohibits "outside parties," including in some cases national unions, from helping workers organize.