Fearless reporter got the scoop - but her methods were dubious; Witness to War: A Biography of Marguerite Higgins, by Antoinette May. New York/Toronto: Beaufort Books Inc. 274 pp. $17.95.

I wish I liked Marguerite Higgins more than I do after reading this book. She was a remarkable journalist, to be sure, a dauntless woman who covered the sort of major international events and leaders that many journalists only dream about.

As a woman in the same profession, however, I have a quarrel with her techniques - with her ruthless competitiveness and, most particularly, with her apparently complete willingness to use sex as a tool to further her career.

What's particularly bothersome about this book is that author Antoinette May's attitude toward her subject is so adoring. There is no real critical analysis here, only a basically unquestioning and enthusiastic recounting of Miss Higgins's journalistic exploits - an undiscrimi-nating attitude perhaps best summed up in a remark made by one of her colleagues: ''Of course there were people who said she used her femininity to get what she wanted. I suppose she did sometimes. What did it matter? One had to admire her for what she accomplished. Who cares how she lived or who she slept with?''

It is impossible not to admire Marguerite Higgins's long list of accomplishments. In her early 20s, with less than two years of experience as a reporter for the old New York Herald Tribune, she steamrollered her way into an assignment in Europe near the close of World War II. She covered wartime London and Paris, beat the Allied forces to Dachau (in effect, ''liberating'' the concentration camp along with another reporter), and -reported on the Berlin blockade and the Nuremberg trials.

Later, she was transferred to Tokyo - just in time to cover the outbreak of the Korean war. Miss Higgins was one of the first four reporters to reach South Korea after the invasion by North Korea began, and her fearless frontline reporting landed her the Pulitzer Prize for foreign reporting in 1951. She was the first woman to be so honored (although she shared the prize with two male colleagues).

By the end of her career, less than 20 years later, she had become world famous. Among her friends were Jack and Robert Kennedy; among the many leaders she had interviewed were MacArthur, Khrushchev, Eisenhower, Franco, Tito, Nehru, and the Shah of Iran.

As a reporter, she possessed some outstanding attributes - persistence, determination, and courage. And occasionally, ''Witness to War'' succeeds in bringing these qualities - and Miss Higgins - to life. The tale of her experience at Dachau, for example, is moving. It's the account of her distinguished work in Korea, however, that provides the book's only genuinely absorbing passages. Here she faced - and overcame - unmerited discrimination when she was ordered out of the country because the military brass thought ''war was man's work; and woman just didn't belong.'' She returned to the front after General MacArthur himself overturned the order.

Unfortunately, most of the rest of the book fails to make the reader care about Miss Higgins, or her life. The narrative suffers from lapses into cliched writing, biographical lurches, and the utter lack of a critical eye that makes a biography something more than just the telling of a tale. This is an interesting book in parts, but ultimately not a very satisfying one.