The source said schools would be given three years to get ready for the new curriculum, and it would not specifically cover sensitive topics such as the June 4, 1989, crackdown in Tiananmen Square. Schools could start teaching the subject before then if they were ready.

'Maybe some schools can start with three junior grades [at primary school], others can first start the subject from other levels,' he said.

A legislator believes the proposed delay is the result of strong opposition from schools and teachers, who have complained that the subject's hasty introduction was unrealistic.

An Education Bureau spokeswoman would not comment on a possible delay, but said the committee had put forward a revised curriculum, and implementation timetable, for the government to consider.

Chief Executive Donald Tsang Yam-kuen promised to improve Hong Kong pupils' knowledge of the nation in successive policy addresses following remarks by President Hu Jintao on the importance of giving Hong Kong children a better understanding of China's development and identity.

It was initially proposed that schools teach the subject for up to 50 hours a year, or two lessons a week. National education would instil positive values to 'facilitate identity building' through developing 'affection for the country'. Schoolchildren would learn, according to their age, to sing the national anthem, attend national-flag-raising ceremonies, understand the Basic Law, support national sports teams, and appreciate and understand Chinese culture.

Committee chairman Professor Lee Chack-fan said a grace period was only one of the options discussed, and the final decision rested with the government.

Some committee members also said a fresh round of public consultations must be held because of drastic changes to the original curriculum, which they did not elaborate on.

A committee member, who refused to be named, said the Hong Kong national education curriculum should not strictly follow the mainland model. 'We should create a curriculum unique to Hong Kong and make an impact across the border,' he said.

The national education plan has drawn criticism from Catholic Cardinal Joseph Zen Ze-kiun and the pan-democratic camp. Both described it as brainwashing. School principals also lashed out, saying teachers were overloaded trying to cope with changes such as the new junior and senior secondary curriculums, and national education could be covered in subjects such as liberal or social studies.

Legislator Cheung Man-kwong, who represents the education sector, said that even if the introduction of national education was delayed, the government needed to deal with the overlap with other subjects. 'Bulldozing it through is just impossible. This is the consensus from teachers and schools,' he said.

780,849

The number of primary and secondary school students enrolled in 2010/11

- 331,112 primary

- 449,737 secondary