Lee on Monday asked Beijing's legislative body to rule on a Hong Kong request to block foreign lawyers from working on national security cases, after the city's top court ruled that a British lawyer could represent jailed pro-democracy tycoon Jimmy Lai.

Lee said he expected China's National People's Congress Standing Committee to make a ruling on the matter "as soon as possible", although he didn't indicate whether this decision would come before the start of Lai's trial on Thursday.

Hong Kong's Department of Justice has repeatedly tried and failed to prevent British barrister Timothy Owen from representing Lai, one of the most prominent Hong Kong critics of China's Communist Party leadership, in a landmark national security case.

Hong Kong's highest court, the Court of Final Appeal, on Monday dismissed a government bid to block Owen from the trial and impose a "blanket ban" on foreign lawyers working on national security cases.

Lee argued that Beijing's intervention, which would be only the sixth instance of China's top legislative body weighing in on legal matters in Hong Kong, was necessary in part because a foreign lawyer might divulge state secrets or be compromised by a foreign government.

Some legal experts said, however, that this would erode public confidence in Hong Kong's judicial independence, which was guaranteed under the "one country, two systems" arrangement in place since the former British colony was returned to China in 1997.

"What we've seen with interpretations is basically, 'Heads I win, tails you lose," Alvin Cheung, an assistant law professor at Queen's University in Canada, told Reuters.

"Whenever the courts issue a decision that is not in Beijing's favor, the matter is taken out of the hands of the Hong Kong legal system and sent north to Beijing for an answer that is, for all intents and purposes, pre-ordained".

Hong Kong officials, including Lee, said Hong Kong is strongly committed to the rule of law, and its independent judicial power is constitutionally protected.