Responding earlier to the criteria for patriotism laid down by Xinhua, Mr Tsang said the Communist Party ruled the country according to the Chinese constitution and practised socialism on the mainland. Through the enactment of the Basic Law, the Hong Kong Special Administrative Region was established and practised capitalism.

'I think anyone participating in Hong Kong's governance should respect this reality. I think it is the basis of 'one country, two systems', and protects Hong Kong's prosperity and stability in the long run,' Mr Tsang said.

Whether one was patriotic should be left to the public to judge, he said, but patriots should be able to serve both national and Hong Kong interests and would not do anything to harm those interests.

'I am sure those elected to public office should be able to comply with these requirements,' he said.

During the three-hour Legco debate, pro-democracy lawmakers attacked the state media and pro-Beijing politicians for trying to scare off voters in the September elections.

Independent legislator Audrey Eu Yuet-mee said relations between the central government and Hong Kong might worsen if Beijing's propaganda prompted more people to vote for the democrats.

She said the government had the duty to lead the skewed debate back to reasonable discussions.

Few Liberal Party or Democratic Alliance for Betterment of Hong Kong legislators responded to the motion. The Liberals supported keeping functional constituencies, while the DAB said any changes must not bypass Beijing.