TEACHERS at technical institutes yesterday threatened to go on strike after 16 lecturers staged a half-day sit-in to protest against what they say is an unfair pay system. The 500-strong Technical Institutes Teachers' Association warned that its members would stage another sit-in on January 21 involving more than 100 lecturers, if the Government refused to compensate staff hit by changes in entry qualifications for lecturers. Association president Chan Wai-keung said the action would be staged at the weekend because members did not want to disrupt classes. Those involved in yesterday's sit-in outside the Vocational Training Council office in Wan Chai had no classes to conduct in the morning or had asked colleagues to replace them. Mr Chan said teachers would hold an extraordinary meeting after the January 21 sit-in to decide when to strike while school was sitting. The dispute started when the Vocational Training Council changed entry qualifications for lecturers' positions in October 1992, requiring that applicants have an honours degree plus three years' work experience. The previous requirement was a degree and six years' work experience. The council said the change was necessary to make qualification requirements uniform when sub-degree courses from the former Hong Kong Polytechnic came under its umbrella. In 1992, that institution demanded that a lecturer have three years' working experience. Mr Chan said the move was unfair because it meant some lecturers were paid the same, despite the fact there was a difference in the number of years' working experience. He said those lecturers affected should be compensated for the differences - to the tune of between $3,000 and $5,000 per month. The council says 64 of the existing 300 lecturers could receive back pay if the Government agrees to compensation. 'It is a matter of fairness, not just money,' Mr Chan said. The teachers' association was unhappy that the Education and Manpower branch refused to meet its members when they raised the issue in August. The council's administrative secretary, Michael Chan Wai, said it supported the lecturers' position and would continue to help their fight. Asked if the council had prepared an emergency plan for a strike, Mr Chan said: 'I believe the staff members of the council are responsible persons and would not go on strike recklessly. Students' interest is of paramount importance.' A branch spokesman said he hoped the lecturers would drop plans for industrial action because the Government had asked the council for more details and it intended taking a fresh look at the matter.