WHEN loansharks attempted to burn the family home, Ah-keung's parents scrambled to find him a safe haven before fleeing the territory. A local priest managed to secure the 12-year-old boy a place in a shelter for runaways and troubled children run by Youth Outreach - and six weeks later Ah-keung described life there as ''very good, better than home''. The youngster is not sure when he will see his parents again, but at the hostel, based in staff quarters at Chai Wan's Pamela Youde Hospital, his life has become more secure. ''It's noticeable that he has put on weight since he's been here, and his skin looks healthier,'' said Youth Outreach director Father Peter Newbery. ''His stay here has given him the chance to get over the trauma of the experience and us the time to find him long-term accommodation.'' Since it was launched more than a year ago, about 200 youngsters have taken refuge at the hostel and been counselled by its social workers. Another 38 adolescents have been helped by the refuge for girls, which opened next door about six months ago. Youth Outreach this week got a major boost with the donation of a van by the Hongkong School of Motoring. This will help social workers step up their search of Hongkong's streets for runaways, Father Newbery said. ''At least one night a week our social workers are out on the streets looking for runaways. The van simplifies matters,'' he explained. The vehicle will also help Youth Outreach fulfil another of its primary goals - to get to street children before triad groups. According to police figures, 3,315 under 16-year-olds were reported missing last year. A similar number of children were reported missing in 1991. But Father Newbery estimated the real number of runaways to be about five times the official figure. ''According to a survey by the Federation of Youth Groups, one in five cases is reported to police,'' he said. He described factors prompting youngsters to leave home and take to the streets as being particularly strong in Hongkong. ''The home situation may be unsatisfactory physically - it's small, hot and noisy and they may be beaten, argue with siblings or just feel their parents are not interested,'' he said. Runaways located by Youth Outreach workers are offered refuge for two months. During that time they and their parents are counselled in dealing with family problems. Youth Outreach costs about $2 million a year to run, money raised solely from private donations.