A former Justice Department official who supervised the government's suit against International Business Machines Corp. and representatives of the company resumed the rhetoric of their aborted suit yesterday, clashing over which side was to blame for lengthy delays in the 13-year history of the case.

In testimony before a House subcommittee, Lewis Bernstein, the Justice official, was also sharply critical of the decision by Assistant Attorney General William Baxter to dismiss the case four weeks ago. Bernstein ran an investigation of the company that began in 1964 and supervised the litigation until he left government in March 1977.

Asserting that "perseverance and sacrifice was required rather than capitulation," Bernstein said that if the case had continued, IBM "might have consented to structural relief that would have provided an opportunity for competition in the business systems market."

Bernstein said Baxter and his staff misread the case to mean that it was designed to show that IBM illegally maintained a monopoly position in business computer systems.

The government "proved" instead that IBM achieved a monopoly by succeeding at deliberate attempts to eliminate emerging competition, "which was threatening the erosion of its monopoly power" by setting up strategies that were not on their own illegal, but did not provide consumers with better products, prices or services, Bernstein said.

Bernstein also argued that delays "were caused principally by IBM's strategy to avoid a judicial determination of the case on the merits."

Bernstein's contentions were challenged in testimony before the House Judiciary subcommittee on monopolies and commercial law by IBM lead trial counsel Thomas Barr, who said he "certainly did not engage in any tactics to cause delay."

In a joint statement with IBM General Counsel Nicholas deB. Katzenbach, Barr said that not until Baxter's predecessor, Sanford Litvack, took the job in 1980 did any of the other seven assistant attorneys general in office since the suit was filed in 1969 actually review the IBM litigation.

"We are strongly of the view," Barr said, "that the decision to dismiss this case would inevitably have been reached by any competent lawyer with knowledge of antitrust law and policy prepared to devote the necessary time and effort to study the case."

Barr said the case, which he estimated cost $50 million to $100 million a year, was ill-prepared by the government attorneys. He said the government attorneys were inexperienced and engaging in a "fishing expedition which might perhaps yield some results.

"The case should never had been brought. It had no merit. We said so in the beginning. The ever-changing government trial staff kept trying to find some way to prove what couldn't be proved. The problem is that they were allowed to do so without direction or guidance by anyone. That is the abuse for which our client and the public paid."

In another IBM development, the company yesterday abandoned a piece of a joint venture with MCA Inc., Discovision Associates, in the optical videodisc and player market. Pioneer Electronic Corp. became sole owner of Universal Pioneer Corp., although the two partners in the joint venture retained ownership of the basic patent and technology.