The trial of fired White House aide Oliver North opened Tuesday and immediately ran into problems when many prospective jurors said they had heard testimony the defendant gave Congress in return for immunity from prosecution.

U.S. District Judge Gerhard A. Gesell planned to hear arguments later concerning a plan to excuse about 40 people from a group of 54 prospective jurors because in 1987 they had watched North testify before Congress about some of the acts for which he now faces criminal charges.The congressional hearings into the sale of U.S. weapons to Iran and the diversion of proceeds to the Contra rebels in Nicaragua attracted large television audiences.

After quickly excusing five jurors because they had seen portions of North's congressional appearances, Gesell reviewed questionnaires and pulled out three dozen who said they "have heard North's testimony."

The judge said he wants to spend time considering "how we're going to deal with this problem."

Defense attorney Brendan Sullivan also sought to rule out as jurors anyone who in recent days had seen North's 1987 congressional testimony replayed in news reports previewing the start of his trial.

John Keker, who heads the prosecution team for independent counsel Lawrence Walsh, said he wanted to present arguments about the process of disqualifying prospective jurors because they have been exposed to North's testimony.

North, dressed in a dark suit, sat at the defense table as Gesell addressed the prospective jurors. Then they filed out of the courtroom to fill out the questionnaires.

North's trial on charges of lying to Congress, shredding evidence and conspiring to commit tax fraud "arises following a period of fairly intense publicityon television, newspapers, magazines" which will continue, Gesell told the jurors.

The questionnaire carries a written warning not to read or listen to anything about North. The questionnaire also admonishes prospective jurors not to discuss the case with anyone.

Gesell wants to find 50 people out of a pool of 300 who have not been exposed to the congressional testimony of North or other witnesses granted limited immunity from prosecution in exchange for telling their stories to Congress.

Indicted 101/2 months ago, the retired Marine lieutenant colonel is the first figure in the scandal to come to trial.

He could face up to 60 years in prison and $3 million in fines if convicted of all 12 crimes with which he is charged.

North is accused of lying to Congress about his role in funneling money to the Nicaraguan Contra rebels when Congress had banned U.S. aid to them.> He is accused of lying to the attorney general about his role in giving the Contras millions of dollars in profits from the Reagan administration's secret arms sales to Iran.> He also is accused of shredding National Security Council records and participating in a tax fraud conspiracy in which wealthy donors would get tax breaks for contributions to the Contras.

Former national security adviser John Poindexter and arms suppliers Richard Secord and Albert Hakim also face criminal charges, but will be tried separately later.