BEIJING — THOUSANDS of women hoping to attend the United Nations' women's summit in Beijing will miss the meeting because of bureaucratic bungling and Chinese political meddling. Amid the planning and political chaos that has overshadowed the conference, only 20,000 to 25,000 people are expected to be present when the Non-Governmental Organization (NGO) Forum opens Wednesday in the Beijing suburb of Huairou, say conference, diplomatic, and UN officials. Original estimates were for 36,000 attendees. The controversial forum of women's advocacy groups runs parallel to the official proceedings of the fourth World Conference on Women running from Sept. 4 to15 in Beijing. The drastically reduced ranks of women activists mirror the controversy that has swirled around the summit for months. In April, the government announced it was shifting the private forum from a stadium in central Beijing to the city outskirts. Western diplomats said that the Chinese leadership, uneasy over the political succession to ailing paramount leader Deng Xiaoping, are fearful of thousands of boisterous activists. China, which first bid to host the conference in 1991 to boost its international prestige in the aftermath of the Tiananmen Square crackdown, now find the conference a major ordeal, analysts say. The switch enraged women's groups, who charged that China was trying to isolate the meeting. The change also created a backlog of paperwork which, despite an intense last-minute effort to process visas, has delayed many travel documents. Beijing, especially slow in issuing visas, wants to cut the NGO forum to its planned size of about 20,000 women. ''I think we will probably have about 25,000 [participants from abroad],'' says Irene Santiago, executive director of the NGO Forum, admitting that many women will be unable to attend. ''We're working 24 hours a day. So are our Chinese counterparts.'' For the first time, China is sending 5,000 delegates to the NGO meeting. Conference officials criticize China for waiting too long to begin issuing visas, but contend that most of those not attending represent either duplicate registrations or people who have voluntarily withdrawn. Ms. Santiago said that only 2,000 women are still awaiting visas and pointed out that 8,000 visas were issued in a two-day period last week. But UN sources say that Chinese embassies and consulates have been especially slow in issuing travel documents under directions from Beijing, which wants to cut the forum to its planned original size of about 20,000 women. Chinese officials conducting training sessions have instructed Chinese volunteers that only 20,000 to 24,000 people would attend, UN sources say. Last week, for example, the Chinese consulate in San Francisco arbitrarily decided to stop issuing visas. A Western diplomat, who maintains that more than 39,000 women, not 36,000, first registered for the conference, reported that in some embassies and consulates, mainly in the United States, only 1 in 20 approved visas had been issued. As of late last week, the majority of American participants had yet to receive their visas. ''The Chinese embassies and consulates were told to keep a tight grip [on visas],'' a UN official says. That foot-dragging violates a Chinese pledge to accept the more than 30,000 delegates in exchange for UN acquiescence of the Huairou move, Western diplomats say. China also violated its agreement with the UN to issue visas to all NGO participants with accreditation when it announced last week that it would ban up to five activist groups. ''There are a lot of things in the [UN] agreement that are not coming to pass,'' a Western observer says. ''This is causing many people to come here needlessly angry and upset.'' Amid Chinese unease and trepidation, an intense and often bizarre security clampdown is under way. In the wake of what appears to be a disinformation campaign in the Chinese press, many Beijing residents believe that Huairou will host a conclave of lesbians, nudists, and HIV-infected women, Chinese women activists say. To ward off embarrassments, hundreds of nearby village women are being mobilized to join modesty patrols for Beijing and Huairou. The women will carry sheets to wrap around nudists and streakers, activists report. ''Someone told me the other day that the real women's conference is being held in Beijing and the prostitutes' conference is being held in Huairou,'' said one Chinese woman participant. ''People really believe this.'' Thousands of plain-clothes police officers have been summoned to Beijing from throughout the country, Chinese sources say. Riot forces are ready, and squads of women officers have been trained to deal with crowds. An additional 4,000 police will be on patrol in Huairou to prevent feminists from staging demonstrations. Dozens of people have been arrested for prostitution and hooliganism to clean up the capital before the conference. Although private-car traffic is restricted, hundreds of extra taxis have been added and their drivers instructed to report any suspicious conversations with visiting women. ''Part of it is a fear of the unknown,'' says Santiago, the forum organizer. ''I think when people see who the women are who come here, that will very easily dissipate.''