A survey on the price of 729 textbooks found those for secondary students had risen by an average of 5.2 per cent compared with last year, while primary textbook prices had increased by 4.2 per cent.

This follows increases last year of 3.7 per cent for secondary textbooks and 3 per cent for primary.

Of 16 textbooks with the biggest price increases, Longman Hong Kong Education publishes 15. For example, volumes 4A/B of Certificate Mathematics in Action now cost $143, up 11.7 per cent, while the price of volumes 5A/B has risen by 11.8 per cent to $123. Longman said the price rises stemmed from declining student numbers, rising staff costs and increased investment to raise quality. It said the average price increase of its books - at 6 to 7 per cent - was in line with the market's 5 to 8 per cent.

Other reasons for price increases cited by publishers in a response to the Consumer Council survey, included the extra costs involved in designing textbooks for the new senior secondary curriculum and the inclusion of multimedia teaching material and teacher training.

Raymond Jao Ming, chairman of the Federation of Parent Teacher Associations of Hong Kong Eastern District, said textbooks would cost Form One students about $2,600 a year and about $2,000 for Primary One students. 'I'm angry. The increases are unjustified,' he said, adding that some textbooks would cost more just because a few pages had been modified.

Wong Lai-ching, chairman of the Sha Tin District Parents' and Teachers' Association, also said the increases were unreasonable. Many parents would not be able to afford more expensive textbooks, having already spent money on uniforms and transport, she said.

But Tsoi Kai-chun, chairman of the Hong Kong Subsidised Primary Schools Council, said that as curriculums were increasingly designed internally in primary schools and teachers produced their own teaching material, fewer textbooks would have to be bought.

Tso Kai-lok, vice-chairman of Education Convergence and the principal of Elegantia College, said his school sought to reduce the burden on parents by using cheaper and second-hand books. Students would not have to buy textbooks for some subjects, as teachers would prepare notes for them, he said.

The Education and Manpower Bureau said it regularly urged publishers to avoid raising prices unreasonably. A guideline was available for publishers on reducing textbook costs. It also suggested that in choosing textbooks, schools should take into account students' needs and abilities.