Principals and parents in three Kowloon districts blame a government decision to bar pupils from their areas from applying for places in Wan Chai schools for their poorer results in Secondary One place allocations this year.
About 79,000 Primary Six pupils yesterday learnt which schools they would go to.
They will be the first to study in the new senior secondary system in 2009.
Under the new system, school-based assessment - where course work counts towards final exams - will be phased in for all subjects in the Hong Kong Diploma of Secondary Education from 2009.
Tsoi Kai-chun, the principal of Yaumati Catholic Primary School, said 75 per cent of his students had been allocated to one of their first three choices, down from 85 per cent from last year.
Mr Tsoi attributed the drop to the Education and Manpower Bureau's decision in April to bar students in Yau Ma Tei, Tsim Sha Tsui and Mongkok from applying to secondary schools in Wan Chai, where several elite schools are located.
Leung Kee-cheong, the head of Fresh Fish Traders' School, said the decision to block Yau Tsim Mong students from Wan Chai schools had accounted for the less than satisfactory results in his school: two of 63 pupils had been allocated to English-medium secondaries, compared with six in the past.
