HONG KONG/SYDNEY (REUTERS) - One of the 14 foreign judges on Hong Kong's highest court said he had resigned due to concerns over a sweeping new national security law imposed by Beijing on the former British colony, Australia's national broadcaster reported on Friday (Sept 18).

The office of the city's leader Carrie Lam confirmed the resignation of Australian judge James Spigelman but did not give a reason.

Mr Spigelman, the former chief justice of New South Wales, is the first senior judge to resign and publicly criticise the law, passed by China's Parliament.

The Polish-born jurist told the Australian Broadcasting Corporation that he resigned for reasons "related to the content of the national security legislation" but did not elaborate further.

He did not immediately respond to a request from Reuters for comment.

His departure comes amid alarm in local and international legal circles at Beijing's imposition of a national security law on the freewheeling financial hub, which boasts an independent legal system based on the common law.

Under the security legislation, Mrs Lam has the right to select judges for a panel of jurists to handle national security cases.

In the most serious cases, suspects can also be taken to mainland China for trial in its courts that are ultimately controlled by the Communist Party.

"Mr Justice Spigelman tendered to the Chief Executive on 2 September his resignation as a Non-Permanent Judge of the Court of Final Appeal, therefore the Chief Executive revoked his appointment in accordance with the relevant legislation," Mrs Lam's office responded in an e-mail to queries about his departure.

"Mr Justice Spigelman did not give any reason for his resignation," it said.

A spokesman for the Judiciary said they had no further comment to offer.

Mr Spigelman was re-appointed to another three-year term on the Hong Kong court last year.

Foreign judges have long been considered a symbol of Hong Kong's judicial independence, helping to replace traditional role of the Privy Council in London after Britain handed the city back to Chinese rule in 1997.

Hong Kong's mini-constitution, known as the Basic Law, enshrines the independence of the judiciary and states that judges may come from other common law jurisdictions.

But Mrs Lam and her officials have in recent weeks stressed that the city had no "separation of powers", and that the powers of its executive, legislature and judiciary all derived from Beijing.

Even before new laws were enacted, senior judges had told Reuters that the independence of Hong Kong's judicial system was under assault from the Communist Party leadership in Beijing.

Barrister Simon Young, a professor at the University of Hong Kong law school, on Friday urged the government to name the judges cleared for national security work to stop possible speculation that foreign jurists were not welcome.

"The ball is clearly now in the government's court to assure the public it still supports the system of foreign judges on Hong Kong's apex court," he said.

Senior barristers said they believed other senior judges were now considering their futures.

In July, the president of the UK Supreme Court said it was in discussions with the British government to assess the future of UK judges on Hong Kong's top court.

Justice Robert Reed, who also serves on the Hong Kong court, said the new law "contains a number of provisions which give rise to concerns".