White House officials yesterday said a preemptive presidential pardon for former national security adviser John M. Poindexter or fired national security aide Lt. Col. Oliver L. North is not being considered or discussed, but they would not rule out such action by President Reagan if either former aide is tried and convicted.

At the invitation of White House chief of staff Howard H. Baker Jr., White House spokesman Marlin Fitzwater raised the issue with Reagan yesterday as the first item of business during the president's weekly "issues lunch."

Fitzwater said he had told reporters at a morning briefing that "there hadn't been any discussion in the White House" of a pardon.

"That's true," Fitzwater quoted Reagan as replying. "It hasn't been discussed, and I don't want to comment on it."

When a reporter during the briefing observed that Fitzwater was not "slamming the door" on an eventual pardon of Poindexter or North, the spokesman replied, to laughter, "I'm not touching the door. I wouldn't go within 40 yards of that door."

Fitzwater later said pardons for North and Poindexter "apparently were considered as one of the options last December when the administration was trying to find a way to get the facts out as quickly as possible." He said the idea of a pardon was rejected but pointed out that several members of Congress, including House Speaker Jim Wright (D-Tex.), had suggested giving them "full immunity" so they could testify. He said the idea of a presidential pardon was discussed in this context.

White House officials said yesterday that Reagan would not give a preemptive pardon and would not interfere with the process he began when he called for the appointment of the independent counsel who is conducting the criminal investigation of the Iran-contra affair. They declined to speculate on what Reagan might do if Poindexter or North were tried and convicted.

Some conservatives, led by former White House communications director Patrick J. Buchanan, are urging a preemptive pardon. In an article in the Outlook section of The Washington Post Sunday, Buchanan called for Reagan to block any prosecution of North or Poindexter.

"Any indictment of either officer would be an offense against justice that ought not to be permitted by the president, whom they served honorably, faithfully and well," Buchanan wrote.

One White House official who asked not to be named said of Buchanan's advocacy, "Pat's still trying to save Nixon, and he already has his pardon. There is nothing helpful to Reagan about raising a pardon issue that hasn't been discussed."

On Sept. 9, 1974, President Gerald R. Ford pardoned former president Richard M. Nixon, who had been named an unindicted coconspirator in the Watergate case. This action became a political issue in the 1976 presidential campaign, which Ford narrowly lost to Jimmy Carter.

Rep. Louis Stokes (D-Ohio), a member of the House Iran-contra committee, raised the pardon question at yesterday's hearings. Stokes asked Poindexter whether he was aware of a White House discussion on Dec. 16, 1986, in which Reagan, Attorney General Edwin Meese III and then-White House chief of staff Donald T. Regan discussed "giving you and Col. North either congressional immunity or a presidential pardon."

"I don't know anything about that, Mr. Stokes," Poindexter replied.

On Dec. 16, Reagan urged Congress to grant limited immunity to Poindexter and North, declaring in a statement issued by then-White House spokesman Larry Speakes that "there is an urgent need for full disclosure of all facts surrounding the Iranian controversy."

In a briefing the same day, Speakes was asked why the president did not obtain the testimony of Poindexter and North by "promising some form of clemency or pardon" to them.

"Well, certainly executive clemency is available to any president, but this president has not chosen to exercise it in this case," Speakes replied.

Terry Eastland, spokesman for Meese, said yesterday that the attorney general had "no recollection" of a pardon ever being discussed at the Dec. 16 meeting. Regan is expected to be questioned about it when he appears before the committee this week.

Staff researcher Michelle Hall contributed to this report.