The High Court has adjourned the national security trial of former media tycoon Jimmy Lai, which was due to start on Thursday, until December 13.

At a hearing before a three-judge panel, the Department of Justice (DoJ) said it has every reason to believe that Beijing will accept Chief Executive John Lee's request for it to interpret the national security law - a move which could effectively ban Lai from engaging British barrister Tim Owen to defend him.

Anthony Chau from the prosecution noted that the government's move was fully supported by mainland authorities, including Beijing's liaison office and the State Council's Hong Kong and Macau Affairs Office.

Chau said a National People's Congress Standing Committee decision on whether overseas barristers who do not have qualifications to practise in Hong Kong can take part in national security cases here would have far-reaching implications, and asked for a seven-day adjournment to Lai's case.

But the court said it would be more prudent to add a few more days, and postponed the hearing to December 13, with no objection from the defence.

Prosecutors said they may apply for a further adjournment to the trial, depending on Beijing's timetable for an interpretation.

But one of the judges, Alex Lee, said it would be unfair to Lai and other defendants if the trial was repeatedly adjourned without a clear time frame as to when it would commence.

In response, Chau said he believed Beijing would accept the interpretation request shortly, and he would then be able to inform the court of suitable dates for the trial.

Owen was absent from the hearing, with Lai's defence team saying the Immigration Department has withheld his work visa extension.