'We looked at the IB for 18 months and we decided 'no',' he said. 'We didn't want to jump on the bandwagon. We have confidence in the new Hong Kong Diploma of Secondary Education. We think that's the right direction and we are sticking with it.'

Instead, the Bonham Road school would give students the chance to take the International General Certificate of Secondary Education exams and International A-levels up to two years earlier than usual - in addition to the HKDSE. Both exams are offered by British examination boards.

'I don't think there is a need for an alternative to the HKDSE,' Kennard said. 'It offers the breadth and depth required. And I think the IB restricts them in the type of subjects they can take. It doesn't allow students to take a large number of subjects within the sciences, for example.'

IB programmes have spread rapidly across Hong Kong's international school sector, with the number of authorised schools more than doubling in the past two years from 10 to 22, with those offering the diploma up from six to 14.

In February, Creative Secondary School in Tseung Kwan O became the first DSS school to gain authorisation and it is offering the IB Middle Years Programme. Diocesan Boys School in Mong Kok and St Paul's Co-educational School in Mid-Levels are applying to launch IB diploma programmes in Forms Five and Six, with one-year preparatory courses of their own starting this month and next September respectively.

But as schools embark on teaching the new three-year senior secondary curriculum that leads to the HKDSE, further growth of the IB as an alternative within the DSS sector appears to be slowing.

HKUGA College, near Aberdeen, which declared before its launch in 2006 that it would offer the IB diploma, has dropped the plan. Vice-Principal Sydney Wong Chun-kuen said: 'We thought that the staff and manpower would be stretched too thinly if we offered two curriculums.'

The HKBU Affiliated Wong Kam Fai Secondary and Primary School in Sha Tin, which was considering the IB when it opened in 2006, is now focusing on the HKDSE. Head of teaching and learning Iris Lau Wai-han said: 'Right now what we are doing is offering the local curriculum.'

Since it became a DSS school last year, St Stephen's College in Stanley has launched five initiatives including foreign exchanges and a creativity programme. Development office manager Kiki Ko said: 'When we started to think about changing to DSS, it was part of our plan to introduce the IB.

'We have registered with the IB but we haven't yet applied for candidate status. We can't confirm the timetable yet, but we intend to include the IB Diploma as an option.'

One exception is the Lutheran Academy, due to open next year in Tuen Mun. It plans to offer the IB at all levels. Principal-designate Andy Fung Wa-chau said: 'Our plan is to have two classes of the IB and two for the new senior curriculum.'

Cheung Siu-ming, principal of Creative Secondary School, which aims to offer the IB Diploma from next September, said: 'I don't expect a large number of DSS schools to offer the IB. We would encourage parents not to rush to the IB to escape an untried HKDSE. The danger is that they push their child into something that they are not suited to.'

Terence Chang, headmaster of Diocesan Boys School, said: 'Our interest in the IB is to provide an appropriate alternative course of study within a government-funded school for students who are aiming to study at universities abroad. If they are staying in Hong Kong, they can still join the local universities but they will be counted as non-Jupas students.'

Jupas, or the Joint University Programmes Admissions System, is the centralised admissions system for local university.

As there were more places for students applying through Jupas, the chances of getting into university for non-Jupas students were lower for all except the brightest, Chang said.

Betty Law, head of admissions at Hong Kong University of Science and Technology, said: 'Anybody with an IB Diploma is eligible to apply. Normally, if you have a grade of at least 30, you stand a good chance of getting to HKUST regardless of the subject area.'

The University of Hong Kong admitted 43 IB diploma students last year, with scores ranging from 38 to 45.

IB at a glance

The IB Diploma is a two-year programme of international education for students aged 16 to 19.

Students take six subjects and must complete an extended essay, take a course in the theory of knowledge and join their school's creativity, action and service programme. The subjects include a first language and one foreign language, while one subject must be chosen from each of four groups: experimental sciences, maths and computer science, the arts, and individuals and societies.