Strict censorship of the sedition trial of opposition leader Kim Dae Jung and the media's strict adherence to military instructions regarding coverage have led some observers to believe authorities are preparing South Korean public opinion for a harsh sentence, possibly death.

A casual reader of any Seoul newspaper this week might well assume that Kim is using his court-martial as a confessional to admit all the sins the government accuses him of committing.

"Kim Dae Jung Admits Most Accusations," declared a headline in one morning paper in midweek.

In fact, the onetime opposition political leader had admitted only minor details of the government's lengthy indictment and had steadfastly denied the major charge that he was striving last spring to overthrow the government. The admissions got headlines. The denials were not mentioned.

The South Korean press had been decimated by a massive government-ordered purge that took place in the weeks before the trial began on Monday. About 400 persons in the news media were fired, while others were transferred to minor posts. At least 250 writers were dismissed, many because they had objected to a modest censorship last spring.

Longtime observers here say the censorship now is stricter than in any but the most rigid period under the regime of the late president, Park Chung Hee.

As a result, the general public has not been informed that Kim and his associates were unable to find lawyers of their choice, or that he was questioned 15 hours a day for two months, sometimes being stripped naked and brought to the brink of torture in a military detention center.

So far in the trial, the military prosecution has presented no evidence to back up the long indictment and has called no witnesses. The case has consisted almost entirely of a reading of the charges and permission for the defendants to respond.

Kim has admitted attending several political meetings, making certain speeches, and distributing some political funds to supporters last spring. Most of those deeds were public knowledge at the time, which preceded the total military takeover on May 17, and Kim has testified they were part of his intended political campaign for president later this year.

He has repeatedly denied that he encouraged violence or gave any instructions to start the bloody uprising in Kwangju last May. The prosecution claims it has a statement from one rioter who says he was acting on Kim's instruction.

The denials are rarely reflected in the censored press. Foreign reporters rely on pool reports from two colleagues allowed to attend each session.

A typical pool report emerges from the censor's office with the prosecution's allegations intact and the denials marked for deletion.

One pool report contained this statement: "The prosecution argued that Kim had intended to create campus unrest and cause social riots that could topple the government."

The censor left that sentence in the report, but marked for deletion Kim's reply, which was: "It is not true. I thought the situation could be dealt with only through public opinion, not by violence."

One of the charges, that Kim received money for his organization last spring from an American, has been denied by the person mentioned. Edward Baker, a former U.S. congressional aide.

The indictment charges that last April, Kim received money from his brother-in-law, who lives in Maryland, through Baker.

Baker, now a research associate at Harvard's East Asian Legal Service Program, denied ever taking money to Kim, and said he was in Cambridge, Mass., at the time. In a telephone interview, Baker called the charge "quite false." Kim acknowledged this week that he received $10,000 from his brother-in-law.