Former Supreme Court Associate Justice Arthur Goldberg has been offered, and turned down, the post of chief counsel for the House Assasinations Committee, according to informed sources.

Anxious to secure a prestigious replace ment for former counsel Richard A. Sprague, committee members had hoped to announce Goldberg's appointment this wek. But after mulling it over, he decided against taking the job and informed Chairman Loius Stokes (D-Ohio) on Wednesday.

Goldberg, 68, who resigned from the court in 1965 and now practices law here, confirmed in a brief telephone interview that he had been asked to direct the investigation. "I guest it's leaking all over," he said.

According to one source Goldberg had tentatively accepted the job, which Sprague resigned from in late March on the eve of a House vote to continue the life of the embattled committee. But the former associated justice denied this.

"I said I simply could not accept because of my heavy assignments over the next six months," Goldberg said. "I'm presiding over two international arbitrations."

Goldberg said the offer from the committee was a firm one, as he supposed it was earlier when Stokes sought former Watergate special prosecutor Archibald Cox.

The investigation is now being directed by acting chief counsel Alvin B. Lewis Jr., who orginally resigned in the wake of Sprague's forced resignation but then agreed to stay on until a permanent successor could be found.

"They have a serious investigation and I took the proposal seriously," Goldberg said. "But it would be inaccurate to say I expressed great interest."

Stokes had no comment. Goldberg's decision, however, apparently leaves the committee without any active candidates for the job. The panel decided last month to look beyond the staff for a prestigious outsider to enhance the inquiry.