Britain's top judge Tuesday warned Hong Kong of the need for "eternal vigilance" to safeguard its liberties as China looks set to take a hardline stance at discussions this week on election reforms in the city.

David Neuberger's comments come as China's legislature meets to decide how Hong Kong's next leader will be chosen, with public discontent in the former British colony at its highest for years over perceived interference by Beijing.

Neuberger, who also sits part-time on Hong Kong's Court of Final Appeal, said he could see no evidence that judicial independence had been eroded.

"If I felt that the independence of the judiciary in Hong Kong was being undermined then I would either have to speak out or I would have to resign as a judge," he said. "But... I detect no undermining of judicial independence."

Speaking at the Hong Kong Foreign Correspondents' Club, he however stressed: "I enthusiastically subscribe to the notion that the price of liberty is eternal vigilance."

Beijing in June issued its first white paper stipulating how Hong Kong should be governed in what was widely interpreted as a warning to the city not to overstep the boundaries of its autonomy.

It included an assertion that judges should be patriotic and safeguard national security and sovereignty, a sentiment which has angered many in the the city's legal community.

"Any threat to judicial independence has to be headed off at the pass," Neuberger said, noting that British judges had spoken out when politicians tried to meddle.

"But judicial independence is not inconsistent with judicial patriotism.

"The way in which judges demonstrate their patriotism is by an irrevocable and undiluted commitment to the rule of law, which involves resolving disputes independently, fearlessly, honestly, fairly and in accordance with the law, and as efficiently and openly as their capabilities and circumstances admit," said the judge, who heads the Supreme Court in Britain.

- 'Coercive measures' -

China's rubber-stamp legislature is mulling a report from Hong Kong leader Leung Chun-ying on methods to elect the next chief executive in 2017, and is expected to come up with a framework on Sunday for the city's future reforms.

Beijing has promised universal suffrage but has insisted that it vet candidates standing for chief executive.

A pro-democracy group, Occupy Central, has pledged to mobilise thousands of protesters to block the financial district later this year if authorities reject a public right to nominate candidates for the post, who are currently chosen by a largely pro-Beijing committee.

A state-run Chinese newspaper Tuesday called for "coercive measures" against pro-democracy protests.

"If these activities pose a shocking threat to Hong Kong or continue unabated, enormously dampening the city's functions, it is imperative that the Hong Kong government adopt coercive measures," the Global Times said in an editorial.

The paper, which is owned by the Communist Party's mouthpiece the People's Daily and often adopts a nationalist tone, also called on authorities not to give in to pressure.

"Even the worst situation is much better than a constitutional crisis with the rise of a chief executive confronting Beijing that will later be compelled to outlaw him," the paper said.

The government must knock out the campaigners' "unrealistic illusions" and make the most aggressive activists "pay for their illegal confrontational behaviour", it said in the editorial, headlined "No compromise of rule on HK chief".

"As long as we do not allow Hong Kong to fall into the Western sphere of influence, the Chinese mainland and Hong Kong will have inexhaustible resources to make extreme opposition groups and their supporting forces desperate," it added.