Foreign judges in Hong Kong have come under scrutiny after a mainland China scholar argued that judges in the region's top court should be local experts.

The comments by Tsinghua University professor Cheng Jie, as reported by the South China Morning Post, included the assertion that Hong Kong's Court of Final Appeal was not just a court for Hong Kong but also "a national court", and as such all judges should be Chinese nationals, or at least have Hong Kong permanent residency.

The remarks came in the wake of a statement by former Hong Kong justice secretary Elsie Leung Oi-sie, who said that the region's legal sector, and judges in particular, did not understand the relationship between Hong Kong and Beijing.

The comments have sparked heated debate among justice officials and industry leaders in the region, evoking wider concerns about Hong Kong's judicial independence – which is seen as being upheld by foreign judges.

"[The comments are] not surpising, because Beijing has always been saying that courts in Hong Kong on basic issues are not particularly reliable," said Professor Fu Hualing, the head of the legal faculty at the University of Hong Kong.

"Most people want to have foreign judges in Hong Kong's legal community, but you occasionally have people from China raising an eyebrow, saying you can't trust a foreigner in Hong Kong making important decisions.

"The wider issue is about the identity of Hong Kong, and to what degree it is still part of China. There are people who think Hong Kong may be drifting away from China 15 years after reunification… and of course the judiciary is a crucial part of it."

Under the Hong Kong Basic Law, only the Chief Justice of the Court of Final Appeal and the Chief Judge of the High Court are required to be local citizens, which means judges from the UK, New Zealand and Australia regularly participate in local trials.

The rules are unlike those in other jurisdictions such as the US and Canada, where local citizenship is a prerequisite to sit in the Supreme Court.

Currently 10 of the 15 judges in Hong Kong's Court of Final Appeal are foreign, typically from Commonwealth countries, while the majority are also non-permanent.

Former chief justice Andrew Li Kwok-nang has subsequently called for the legal sector to maintain its judicial independence by holding on to the provisions of the Basic Law.

The Hong Kong Bar Association has also spoken out in defence of foreign judges, saying that any shake-up in Hong Kong's top court would contradict the Sino-British Joint Declaration signed in 1984, which stipulated a "one country, two systems" principle.

Local experts perceive the comments as an attempt to put pressure on the Hong Kong legal system, but believe they are unlikely to spark any radical change in the short term.

"It will be difficult to change [the criteria for judges] unless you change the law, and I don't think Beijing will change the law," said Fu. "The pressure will be very subtle, in the hopes that [in the long term] the courts will exercise some form of self-censorship."