ONE of 129 Vietnamese boat people repatriated yesterday said Hong Kong officials had threatened them with tear-gassing if they did not return to Vietnam. Tran Trung Dung, who had friends killed in the 1992 Sek Kong fire and whose wife deserted him during his stay in Hong Kong, said he decided to volunteer to leave after the threats. ''I was told that if we didn't go back to Vietnam there would be trouble and that the same thing that happened in section seven [of the Whitehead Detention Centre] could happen to us, only worse,'' he said. Mr Tran, 37, was in section five at Whitehead on April 7 - the day 1,250 Correctional Services Department (CSD) and police officers stormed the compound firing 557 canisters of tear-gas in what was officially termed a transfer operation. He said CSD staff and a UNHCR officer both said the raid on section seven was something that could happen to himself and others. ''Only one day after the raid they said this, and I immediately signed up to go to Vietnam. ''Many people who came on the flight to Vietnam with me felt also that if they didn't go their children could be hurt like the ones in section seven.'' More than 270 people sought treatment for burns and other injuries in the days after the raid, which is now the subject of an independent inquiry ordered by Governor Chris Patten. Commissioner for Correctional Services Eric McCosh last night said he could not comment on Mr Tran's allegations as there was no information about who the officials were and under what circumstances the alleged threats were made. But, he said he doubted CSD officials would say such things. Mr Tran left Vietnam three years ago, leaving behind his wife. He told her he would send for her when he could. Since then, he has been held in the now closed Sek Kong detention centre - the scene of a fire in 1991 which killed 24 people - Hei Ling Chau, and finally Whitehead. Mr Tran said he had stayed in Hong Kong because he feared retribution if he returned to Vietnam. He fled to Hong Kong after escaping from police, who were holding him for selling smuggled cigarettes. He said it was only last month, after a visit from Vietnamese government officials, that he began to believe that returning home might not be as bad as he thought. ''Finally, after the attack at Whitehead, I had to leave - to give my son a chance . . . and me too.'' The repatriation of yesterday's group coincided with a visit by the United Nations High Commissioner for Refugees, Sadako Ogata, who took time to review the reception centre where Mr Tran was. ''We have to give these people a chance to get on with their lives,'' Mrs Ogata said. She said ''a long look'' would have to be taken at ways of clearing detention centres in the region by the end of next year, according to the plan laid down by the international community. The commissioner, who leaves for Bangkok on Saturday, said she held ''positive'' discussions with the Vietnamese Prime Minister Vo Van Kiet yesterday.