CHINA has finally agreed to take back more than 1,000 Vietnamese illegal immigrants being held in detention centres after they flooded into Hongkong from Guangxi province earlier this month. But the Beijing authorities are still refusing to deal directly with the Hongkong Government and have instead requested cash and assistance from the United Nations High Commissioner for Refugees (UNHCR). The Chinese attitude is frustrating Hongkong officials, who want to repatriate the immigrants as soon as possible to dissuade perhaps thousands more Vietnamese, whose homes in Beihai were pulled down for redevelopment, from trying to reach Hongkong. The Foreign Office in London said the urgency of the matter had been stressed to Chinese officials and they would continue to do so until the situation was resolved. Officials here are ready to start repatriating but say none of their requests to Beijing to discuss details have been answered, although Hongkong will meet the full cost. Instead, the Chinese Government has approached the UNHCR for cash and assistance. The UNHCR refused to reveal details of the request made to its Geneva headquarters through its Beijing branch, though the deputy chief of the Hongkong mission, Kaiser Zaman, said it would support the early return of the illegal immigrants. Yesterday morning, Marine Police arrested 33 ex-China Vietnamese illegal immigrants on one boat. Some 29 boats with 1,155 Vietnamese illegal immigrants have been intercepted in Hongkong waters this month. The Chinese Foreign Ministry said yesterday it was concerned about the illegal influx into Hongkong of Vietnamese claiming to be from Beihai and would take them back as soon as possible, while initiating action to stop further boatloads sailing to the territory. But the Refugee Co-ordinator of the Hongkong Government, Brian Bresnihan, said the Chinese had not replied to repeated requests to arrange for the return of the immigrants to Beihai. He said it was a matter for the UNHCR to decide whether to give assistance to the Chinese Government, but the normal practice was for costs of repatriation to be met by the country where the immigrants had landed - in this case, Hongkong. The Chinese statement appeared to criticise Hongkong for the second time in a week and called on officials here to take ''effective measures'' to stop the flow. ''They [the Chinese authorities] will, as they did before, make arrangements in collaboration with other departments concerned, to take back as soon as possible those Vietnamese refugees who are proved to have been resettled on the mainland but have entered Hongkong illegally, once their identities are verified,'' a spokesman said. ''The Chinese side has always held an attitude of active co-operation toward this matter. It is hoped that the British Hongkong Government will also take effective measures to help properly settle the issue.'' Mr Bresnihan said he welcomed the statement that China would take back the illegal immigrants, adding that Hongkong was ready to co-operate. ''The ex-China Vietnamese illegal immigrants in Hongkong will have to be repatriated quickly to deter more people from coming,'' he said. ''This is the point that we put to the Chinese and this is the question on which we are still awaiting a reply. ''We have given full information on all the individual illegal immigrants to China. We are just waiting for a response.'' The Hongkong Government would meet the cost of repatriation and would arrange the transportation, Mr Bresnihan added. ''The normal way would be across the border, but we would look very sympathetically on proposals for alternative modes of repatriation if they are required,'' he said. An operation similar to the 1987 repatriation of 2,000 Vietnamese refugees, who were shipped to Beihai on board a Macau ferry, has not been ruled out. A Security Branch spokesman said illegal immigrants were being moved from Green Island to the Chi Ma Wan detention centre, where there was still space. Resources were being stretched, but the situation remained under control. he said.