SEOUL, JULY 1 -- -- South Korean President Chun Doo Hwan this morning agreed to release political prisoners as part of a major package of democratic reforms. Now comes the hard part -- agreeing with the opposition on what a political prisoner is.

Chun gave some sign of the discord that seems certain to lie ahead when he said in a nationwide television address that political prisoners will go free "except for a very small number of felonious offenders."

Christian human rights activists here list about 1,850 people whom they regard as political prisoners. The government says there are about 1,150, and the opposition already is alleging that the government intends to release far fewer than it says.

Korean jails have no shortage of "prisoners of conscience," people serving time for the peaceful expression of political beliefs that run counter to the government's.

The law here provides that people can be arrested for defaming the state. Most demonstrations are illegal. Any statement that matches the political line of communist North Korea also can be grounds for prosecution.

But in recent years, many of Chun's opponents, particularly students, have felt justified in using violence against a government they believe is a brutal military dictatorship.

The opposition now wants all prisoners released, regardless of their means of protest. "We have to consider the situation that has forced people into using rocks and molotov cocktails," said a human rights worker.

The government maintains a huge domestic security and intelligence apparatus, both civilian and military. Officials justify it as necessary to guard against subversion from North Korea.

Dissidents, however, see its main purpose as rooting out opposition to whatever government is in power.

Most people picked up by police here are released quickly, but often only after questioning that might involve violence. During demonstrations that began June 10, police hauled away more than 17,000 people, all but about 300 of whom were released almost immediately.

Those held for prosecution tend to be protest leaders and organizers. They are charged under a wide variety of broadly worded laws covering national security, public assembly and demonstrations, among other things.

The Washington-based human rights group Asia Watch estimates that in 1986 more than 500 people in South Korea were convicted under laws on public assembly. The group says more than 300 people were convicted under the national security law.

Church officials here suggest that the discrepancy between the government's and the opposition's count of political prisoners may result from the government ignoring those convicted under the national security law.

Soh Won Ki, 32, was accused under that law, his family says. He was arrested in April and accused of supporting an underground labor union movement.

His wife, Lee Kyong Eun, says his only link to the movement was in providing about $25 a month to help support a friend who was a full-time labor activist.

Soh's family alleges that he was stripped to his underwear and subjected to water and electrical torture in a military facility for two days after his arrest. They say he later was moved to a police center and beaten daily.

Reports of torture in jails are common, made more credible by official acknowledgement in January that an arrested student had died while having his head forced into a water-filled bathtub during interrogation.

Still, Latin American-style "disappearances" and political murders are virtually unknown here. South Korean police prefer to operate within the framework of the law -- but they define that framework.

People arrested here generally can get word to their families. Suspects eventually get a trial, though one that may be stacked against them from the start.

Now that Chun has promised to release political prisoners, newspapers here report that Justice Ministry officials have begun screening individual cases for consideration for release. Prisoners held since 1980 will get priority, according to reports.

Today, about 300 relatives of political prisoners went to the offices of the opposition Reunification Democratic Party to press for action.

"My son was tortured into confessing to arson," said one woman at the party's office. "There are many cases like that."