A federal judge today ordered that certain transcripts and videotapes of meetings between FBI undercover agents and Sen. Harrison A. Williams (D-N.J.) be turned over to attorneys representing four Abscam defendants scheduled to go on trial next week.

District Court Judge John P. Fullman ordered the government to make available to the defense the transcripts and tapes referred to in the "Del Tufo Memorandum," written by Robert J. Del Tufo when he was U.S. attorney for New Jersey.

The memorandum, addressed to officials in the Justice Department, reportedly criticizes the techniques of FBI undercover agents and discusses the Abscam investigation. Dfense attorneys have asked to see the memorandum, but Fullman has refused.

Today, however, he ordered that the transcripts and tapes discussed by Del Tufo be given to the defense "as promptly as possible, and in no event later than Friday." Fullman is scheduled to preside over the Abscam trial when it opens here Monday.

On trial will be Philadelphia City Councilmen George X. Schwartz, Harry P. Jannotti and Louis C. Johanson and Philadelphia lawyer Howard L. Criden. The four are accused of accepting $70,000 in bribes at the Barclay Hotel in January from FBI agents posing as representatives of a fictitous Arab sheik.

News reports have indicated that Williams was under investigation for alleged agreeing to help the fictitious Arabs win defense contrasts in exchange for their help in financing a titanium mine in which Williams would own some stock. Williams has not been charged with any wrongdoing in connection with the Abscam probe.