Oliver North Wednesday blamed former national security adviser Robert McFarlane for sending a letter to Congress that falsely denied the National Security Council staff was assisting the Contra rebels in Nicaragua.

As the former NSC aide took the stand for the fifth day at his Iran-Contra trial, prosecutor John Keker read aloud a section of a proposed response to then-Rep. Michael Barnes saying, "None of us has solicited funds or coordinated the military efforts of the resistance.""That statement is untrue and I did not put it in there," North said of the draft letter to Barnes, D-Md. He said McFarlane, then his boss, "had written his own" letter on Sept. 12, 1985.

"What did you do to straighten it out?" Keker asked.

"I am quite certain I didn't do much at all," North replied. He said McFarlane "had already put this kind of language in his letter" on Sept. 5, 1985 to Rep. Lee Hamilton, D-Ind., then the chairman of the House Intelligence Committee.

"I wrote a number of other letters" that were "inconsistent with the facts. I just simply do not believe I wrote this letter," said North. "Those words are written in Mr. McFarlane's handwriting."

Keker interjected: "And apparently sent to you for editing."

"And that is a point I would contest because I don't believe it was sent to me for editing," North said.

Among 12 criminal counts, North is accused of making a false statement to Congress in connection with the letters to Barnes and Hamilton. No charges have been filed against him in connection with letters he says he wrote on Contra support to at least one other congressman and two senators.

Meanwhile, documents released at the trial suggest North deceived President Reagan's lawyers by saying that a fund-raiser and wealthy donor weren't providing money to the Contras.

As a result of those assurances, Reagan got the go-ahead from White House Counsel Fred Fielding to send thank-you notes to Carl "Spitz" Channell and Barbara Newington for their support of the administration's policy in Central America.

In an Oct. 7, 1985 memorandum to Reagan, North described Mrs. Newington as a "stalwart supporter of your Presidency" and Channell's organization as providing "paid television advertising in support of your policies in Central America."

Mrs. Newington, a Connecticut widow, donated $2.8 million to the Nicaragua rebels through Channell's tax-exempt organization, according to records.