Hong Kong's second-largest teaching union has launched an attempt to unite the education sector behind a battle against the closure of secondary schools due to falling rolls. The Hong Kong Federation of Education Workers yesterday unveiled an 'anti-school closure campaign' and invited 20 educational associations including the Professional Teachers' Union and all secondary school heads associations to join. PTU leaders vowed before the start of term to roll out a series of protest actions to support 10 demands to save schools from closure - focused on reducing class sizes - which they have put to the Education Bureau. The move put them on a collision course with a joint committee of principals' associations, which is working hard to persuade schools to join the bureau's voluntary class reduction scheme. But the Beijing loyalist federation, which represents some 20,000 teachers and is funded by the Hong Kong government to run the national education programme, is seeking to build bridges between the two sides. Chairman Wong Kwan-yu said: 'We need to put aside our differences and sit down and find common ground so that we can have a united front to negotiate with the government.' Wong said the federation was also demanding an increase in the teacher-to-class ratio to from 2:1 to 2.2:1 by 2012, a reduction in the maximum class size to 30 by 2012, and for all schools with a 24-classroom campus to be required to cut Form One classes from five to four by September next year. All the demands were backed by the majority of teachers in a survey that found more than 70 per cent were 'worried' or 'extremely worried' about school closures, he said. There are 69,000 Form One students this year - about 7,000 fewer than last year - and student rolls are set to fall by a further 21.9 per cent until the 2016-17 school year, when there are projected to be 53,900 Form One students. Some 30 schools are facing the threat of closure next year after they failed to recruit the minimum 61 primary school leavers that is required to operate Form One classes this year. The bureau launched a voluntary class reduction scheme earlier this year to address the problem, but only 23 schools joined its first phase starting this month. PTU president Fong Wai-wah said it would not be joining the federation's campaign because the PTU represented 85 per cent of all teachers and did not need the backing of other organisations. Meanwhile, nearly 90 per cent of teachers believe their workload has increased in the past three years, a survey has found. More than 57 per cent of teachers worked more than 61 hours a week on average, the study by the Hong Kong Institute of Education found.