THE 30,000th Vietnamese to go home voluntarily from Hongkong is scheduled to board a repatriation flight today. But repatriation rates have slipped behind other areas in the region. European Community International Programme spokesman for Vietnam, Lorna Workman, said 790 Vietnamese had returned home voluntarily from Thailand last month, compared with 535 from Hongkong. It was the first time the number returning from Hongkong had fallen below that of Thailand. ''Thailand has been the centre for the Vietnamese boat people, but the ministry has been very strict telling those who have been screened out twice they have to go home. All they get is medical services, food and clothing, and primary education.'' Indonesia had also given a clear signal it wanted to redevelop the island on which 10,000 Vietnamese boat people were housed. Indonesia and Thailand have both estimated they can clear their camps by next year. Hongkong's estimate is by about 1996. The comparative drop is more significant given the territory has as many boat people as the rest of Southeast Asia. The United Nations High Commissioner for Refugees (UNHCR) chief of mission, Robert Van Leeuwen, will join the estimated 150 Vietnamese on today's flight to Hanoi. The departures will reduce to 40,845 the total remaining in the territory's camps, including 31,458 who have been screened. Some are waiting for a review decision. The UNHCR said that more than 43,000 boat people had returned voluntarily from first-asylum countries including Hongkong. Ms Workman said Hongkong's boat people were a complex mix, compared to Thailand which had mostly southerners who tended to be economic migrants. Hongkong's rate also was linked to inactivity after long periods in detention, ignorance of changes in Vietnam, and scepticism about information. Resistance to repatriation was often based on the perception that the screening process was unfair, said Refugee Concern Hongkong spokeswoman Pam Baker. ''Most of those who are still here feel the screening process has been unfair. They will simply be too terrified to go home because they know in their hearts they are refugees.'' Meanwhile, the UNHCR repeated a warning that cash incentives of US$360 for individual non-refugees would be reviewed. Major re-integration programmes such as the EC International Programme and the Nordic Assistance to Repatriated Vietnamese are also expected to close next year.