He said the time before 2012, when the inaugural Hong Kong Diploma of Secondary Examination would replace the Form Five and Seven public exams, was a critical period to promote its credentials.

'I feel honoured to be part of the critical part of the education reform. I am confident I can achieve the historical mission,' Tong said.

Led by Cheung, the examinations authority has been busy in recent years promoting the diploma exam overseas.

It so far has gained the recognition of universities in Canada, the United States, Britain and Australia.

Another priority is to further enhance the effectiveness of liberal studies, a new compulsory subject for senior secondary students since last year.

'It means a great deal for the government to introduce a subject with inquiry-based learning,' Tong said.

'[Mastering] the subject is not a stepping stone to university education. It's aim is to nurture the all-round development of students.'

The assessment methods for the subject, which some critics say require subjectivity on the part of markers, have long been maligned by the public.

But Tong said he was not worried by the dissatisfaction. He said: 'Every assessment system produces scorers of high and low marks.

'Now, the diploma uses a new system where students' performance is measured against a set of yardsticks. All people who fulfil the yardsticks will be awarded their worthy grade.'

Chairman of the authority Eddie Ng Hak-kim said Tong would give the authority an image overhaul.

'There's a whole new plan to be more open and transparent,' he said. 'We have told our staff to replace the word 'authority' in correspondence with 'us' to water down the rather bureaucratic connotations of the word.'

Tong, who joined Baptist University in 1992 as a mathematics lecturer and took up the post of registrar in 2008, said the transparency of the authority could be enhanced by organising more information days, press conferences and forums.