UNSCRUPULOUS teenagers are using Hong Kong's student nursing courses to make ''easy summer money'' and leaving after only a few weeks to attend university or the polytechnic. More than 25 per cent of the 240 who enrolled in the nursing course which began in June have already left, having earned more than $16,000, to continue with their tertiary education, said the principal of one English nursing school. ''Many students join to earn money in the summer,'' he said. The courses start in February, June and October. Many students sign up in June after their school year ends and leave at the end of August in time to start university. The principal said over the past three years, more than half the students dropped out of the June course in the first few months while only eight to 15 per cent dropped out of the other two courses. A nurse at the Queen Mary Hospital said students were tempted to enrol for an ''easy summer''. Nursing students only have four to five one-hour lessons each day between 8 am and 4 pm on weekdays and for a few hours on Saturday mornings. During the first eight weeks of the three-year training programme, students study basic nursing, dissection, psychology, micro-biology and medical hygiene. Garnering practical experience in hospital wards only starts in the ninth week. According to the nurse, the students have ''very little homework'' and are paid $8,000 a month - more than most summer jobs pay. The principal said because the Queen Elizabeth, Queen Mary, Princess Margaret, Prince of Wales and Tuen Mun hospitals wanted students with top academic results, they attracted these ''irresponsible'' teenagers. Officials from hospitals teaching the Chinese nursing course said the number of students dropping out this summer was less than in previous years but admitted it was still a serious problem. The Hospital Authority's senior executive manager, Lai King-kwong, admitted the June course drop-out rate was a problem. He said the authority was doing a survey of the wastage at nursing schools and was interviewing those who had left. The results are expected next month. The principal has called for the June course to be abolished to prevent abuse and has suggested a contract system for students signing up. He said there would be no point in reducing the salary because it was an investment in their future. Mr Lai also said it would be unfair to lower salaries. ''We also have to compete with other professions so we must pay a reasonable salary. Otherwise, they will do other jobs.'' Legislative representative for the medical constituency, Dr Leong Che-hung, accused the students of cheating the Hospital Authority and called them ''immoral''. ''The students should sign contracts so that they have to compensate the HA if they don't finish the course,'' he said. Dr Leong also criticised the HA's policy of each hospital running its own school and called for centralised co-ordination on the budgets for nursing courses.