Saying that he had been burned by Washington "powercrats" before, Bert Lance yesterday refused to give a deposition to the Senate subcommittee investigating Billy Carter unless it was conducted in public.

Lance said he was afraid that a distorted picture of whatever he said in private would be leaked to reporters.

The former Georgia banker and confidant of President Carter delivered his ultimatum to subcommittee lawyers here yesterday afternoon and marched out again after an unproductive 45-minute meeting. He said the next step is up to them.

Recalling the prolonged government investigations of his business dealings, culminating in his indictment and subsequent acquittal, Lance said he felt strongly that he should be permitted to testify in public, right at the outset, "in order that the whole story might be given at one time."

The subcommittee has been seeking to question Lance about a reported contact with a foreign banker in connection with projected Libyan business deals that Billy Carter was considering. The senators also want to ask Lance about his conversations with President Carter concerning Billy Carter over the past two years.

Accompanied by his wife, LaBelle their sons, David and Beverly, and a trio of lawyers, Lance said he did little more than read a prepared statement, which he read again later for reporters.

In it, he said he had been victimized in the past by "well-planned and well-conceived leaks to the media about testimony or information taken in private," and that he did not intend to let it happen again.

"What few of my constitutional rights that were preserved and protected during the three years of the Lance affair," he said, "resulated from the daily presence of the media at my trial."

Accused of bank fraud in his financial dealings in Georgia, the former director of the Office of Management and Budget was acquitted in April of most of the charges after a 16-week trial. The Justice Department decided not to try to prosecute him again on the three counts on which the jury could not agree.

Lance said he told the subcommittee's lawyers that if they refused "to let the sunshine in" by opening up the deposition, he would let them make the next move. Asked if he would go to jail before giving in, he did not answer directly, but made plain that he did not expect it to come to that.

"We don't have any reason whatsoever to have any fear or trepidation," Lance said of himself and his wife.

He said he was not involved, directly or indirectly, in assisting Billy Carter in his dealings with the Libyans and that he knew nothing of any projected commission that Billy Carter was anticipating from the sale of Libyan oil.

Lance refused to comment when asked about my conversations he had with the president concerning Billy Carter over the past two years. "That's a part I'm not going to get into," he told reporters.

In his report to the Senate subcommittee last month, President Carter said his notes showed he had talked with Lance about his brother on Feb. 24, 1979, when Billy Carter, who had been drinking heavily, was in an Americus, Ga., hospital. According to the president's notes:

"He's [Lance's] to visit Billy this coming week, to encourage him to take care his health, his finances and to stay away from Libya for a while."

Billy Carter's sidekick, Henry R. (Randy) Coleman, said in Senate testimony several weeks ago that Lance had given him the name of a banker in London whom Coleman saw on the way back from a March 1979 trip to Rome to investigate possible commodity trading deals for Billy Carter. Apparently nothing came of the contact.

As Lance met with reporters outside one Senate hearing room, members of the subcommittee were gathering in another to hear from CIA Director Stansfield Turner and other witnesses at an executive session.

Sources said Turner was questioned closely, and skeptically, about his notifying the White House in March that Billy Carter was attempting to win a bigger allocation of crude oil for a U.S. oil company.

Turner gave the news to White House national security adviser Zbigniew Brzezinski, who promptly called Billy Carter and warned him not to do anything that might embarass the government.

At the closed session, Turner reportedly maintained that he had done the right thing in notifying Brzezinski, and the Brzezinski had been right to call the president's brother.

Members of the subcommittee were incredulous, sources said.

"That just won't wash, admiral," Sen. Max Baucus (D-Mont.) was quoted by one source as saying.

Sen. Bob Dole (R-Kan.) reportedly said he would just pick up a telephone and call everyone else mentioned in the intelligence report Turner saw, and warn them to be careful, too.

"No, no," Turner replied, according to one source, "You can't do that."