UNITED NATIONS, JULY 23 -- The United Nations said today it would convene a meeting in September at which members of the former U.N. War Crimes Commission are expected to endorse the opening of archives on some 40,000 suspected Nazi war criminals.

U.N. officials indicated that at least 12 of the 17 nations on the now-disbanded commission favor some form of scholarly access to the 40-year-old dossiers. They said Secretary General Javier Perez de Cuellar is likely to use the meeting, tentatively set for Sept. 22, as a basis for easing the stringent rules under which copies of the files can only be turned over to governments, and only on the condition that the contents not be divulged.

The secretary general, after consultation with members of the former commission, may change the rules governing the archives.

The issue of wider access arose in April 1986, after former U.N. secretary general Kurt Waldheim was charged with misrepresenting his World War II record. Waldheim has been accused of playing a subsidiary role in Nazi crimes against Jews in Greece and against partisans and war prisoners in Yugoslavia. Waldheim, now the president of Austria, was found to have a dossier in the U.N. files, which were gathering dust in a Manhattan warehouse.

His name also turned up on the master list of the war crimes commission files, available to the public at a U.S. warehouse in Maryland. The commission disbanded and turned its files over to the United Nations in 1948.

Israel, renewing a year-old request, asked in March that the archives be opened, and lobbied intensively in all 17 capitals. Washington had initially opposed access to all but governments and their law enforcement agencies, but last month endorsed the idea that each government should be allowed to set criteria for allowing its citizens access. The United States indicated that it planned to grant access to all but those who clearly intended to misuse the data. However, the government added that it would regard the screening process as a formality.

Israel takes a similar view, but most other nations have suggested more stringent criteria, such as limiting access to "scholarly usage" or "serious academic researchers."

At a press conference here today, Israeli Ambassador Johanan Bein announced that Israel had now received all 2,400 of the individual files it had asked of the United Nations. These will be sent to researchers at Yad Vashem, the Israeli Holocaust memorial center.

Researchers "believe significant new information will be revealed," Bein said. But he cautioned that because of the passage of time since World War II, there was little hope that material could be found to track down war criminals who might still be at large.

Each of the dossiers is in English, and contains raw reports as well as analysis of evidence collected against the individual. The analysis includes a coded recommendation on whether the person should be prosecuted.