"China's top lawmaking body has given Hong Kong leader John Lee the power to bar foreign lawyers from national security cases, removing the decision from the city's courts, in a move likely to further fuel concerns over judicial independence.

The move, reported by state news agency Xinhua on Friday, comes after a Hong Kong court this month postponed a national security trial against media tycoon and China critic Jimmy Lai to September, to give time for the ruling by China's National People's Congress Standing Committee.

Critics say Beijing's intervention in this landmark legal case undermines Hong Kong's judicial independence, after a panel of three senior judges on the city's Court of Final Appeal in November rejected a government bid to block Owen from representing Lai.

The NPCSC ruling said Hong Kong courts must now obtain approval from the chief executive before admitting any foreign lawyer without local qualifications to work on national security cases.

Lee said in a news conference late on Friday the decision only involves "a very small area" as they are only looking at whether overseas lawyers should be allowed to take part in national security cases.

Legal scholar Eric Lai said on Twitter that the decision "Creates a de facto political-legal committee for Hong Kong", as judicial independence vanishes when executive authorities can override a court decision without being challenged by a judicial review.

The founder of now shut pro-democracy newspaper Apple Daily, Lai is one of the most prominent Hong Kong critics of China's Communist Party leadership, including Xi Jinping. "