It would also allow the former Independent Commission Against Corruption commissioner to answer questions without compromising an ongoing criminal investigation into his conduct being carried out by the agency he used to head.

Tong looked haggard as he faced questions over the ICAC spending on anti-graft education, two lavish dinners he hosted and his approval of expenditure which exceeded permitted spending levels and which were revealed in an official audit report last month.

The former high-ranking civil servant, who is a member of the Chinese People's Political Consultative Conference, the nation's top political advisory body, did not offer any apology when he faced the press after the hearing.

He said only that he respected the proceedings, as well as the other inquiries being carried out into his actions, and would face them calmly.

"If the hearing finds Tong Hin-ming is wrong, [I] will admit my wrongdoing and bear responsibility. If it clarifies any facts, of course I would also gladly accept that," he said.

Tong emphasised that being corruption-free is a core value of Hong Kong, but said there had been "great pressure", without elaborating.

On several occasions Tong said he could not give a definitive answer to a question because he hadn't had enough time to review the details of expenditure on earlier dates.

He also consulted his legal team of barrister Peter Wong Ting-kwong and lawyer Michelle Hui several times before answering questions.

Lawmaker Alan Leong Ka-kit said: "I have sat here for more than an hour with my greatest patience ... there is nothing he has said that can answer our questions. It is a waste of time."

Committee chairman Abraham Razack said he had expected Tong would be cautious when taking questions because he was now under criminal investigation.

According to Legco rules, the committee can invite any person to give information or explanations, but the person can refuse to do so and what they say is not protected by legal privilege.

One of the focuses of the audit reports was two lavish dinners Tong hosted in 2011. At one dinner, the expenses for wine and desserts were calculated separately so the dinner did not exceed the permitted limit.

Simon Peh, the current ICAC commissioner, said that between 2003 and 2013, the ICAC's community relations department hosted 548 official receptions, and alcohol expenses were calculated separately for 12 of them.

He said the expenses for only four meals exceeded the permitted level once the cost of alcohol was included. The level was exceeded by between HK$11 and HK$132 per head.

He said his staff often bought alcohol separately, instead of ordering it at a restaurant, as it would be cheaper.

Peh appeared at the hearing before Tong. He asked the committee to appear separately from Tong to avoid any conflict or suspicion because he is leading an investigation into Tong's actions. Razack accepted the request.

The committee heard that the expenditure of the ICAC's administrative branch, which covered some of the expenses in question, was HK$48 million in the 2008-09 financial year, exceeding the expenses of the community relations department.

Before Tong took office, the branch only spent half as much as the community relations department.