But after a thorough investigation the Department of Justice (DOJ) concluded there was not enough evidence to press charges against Leung, and decided not to seek outside legal advice on the matter.

“I hope the minister will think about why citizens still have many doubts,” Kwok said before his motion was put to vote in the chamber.

But the non-binding motion, which required a majority in both the functional and geographical constituencies, failed.

In the geographical seats, 15 lawmakers voted in support and 16 voted against, while the motion only had nine votes in favour in the functional seats, to 24 against.

The pan-democrats have asked if Cheng, who has the final say on prosecutorial decisions, deviated from standard practice by not seeking the opinion of independent counsel in the case.

In the past, the department sought outside advice before concluding sensitive cases involving former officials, such as former chief executive Donald Tsang Yam-kuen and former chief secretary Rafael Hui Si-yan.

Before the vote, Cheng said passing the motion could lead to a trial by public opinion should she then be forced to make elements of the case public.

Will lawmakers burned by Carrie Lam give Teresa Cheng a good grilling?

The justice secretary also said whether a case was sensitive or not was not the sole factor when deciding if the department should get outside counsel.

“If the DOJ is capable of handling a request for legal advice, and when the case does not involve particularly difficult legal issues or special circumstances … what is the need for seeking external help?” Cheng said.

She is set to return to Legco next Monday to attend a meeting of the Panel on Administration of Justice and Legal Services, and one hour has been allocated to discuss the DOJ’s prosecution policy.

During Thursday’s debate, pro-establishment lawmaker Abraham Razack said that, though he did not believe Cheng had done anything wrong, Kwok’s motion was not a waste of time.

“I think it is appropriate for [Kwok] to bring the whole motion … so that we bring to an end the dark clouds hanging over Hong Kong in the name of the UGL and CY Leung saga,” Razack said.

The Independent Commission Against Corruption concluded its investigation into Leung last month, after seeking legal advice from the justice department.

Why Hong Kong justice chief Teresa Cheng must go

Leung’s case also sparked public concern that anticorruption laws were not strong enough when it came to dealing with the city’s leaders.

Chief Executive Carrie Lam Cheng Yuet-ngor has vowed to revise the parts of the Prevention of Bribery Ordinance that cover the top post, after studying any related legal and constitutional issues.

Soon after taking office, Chief Secretary Matthew Cheung Kin-chung promised that after completing the study the government would “initiate the legislative process” as early as possible.

But more than two years later, Cheung said the study was still in progress and would “report its findings to the Legislative Council” as soon as possible, without touching on legislation.

Lam’s top advisers previously suggested she may fall short of tightening the rules surrounding bribery in her first term.

“We’re just hoping for more time to seek a possible proposal,” Cheung said.

Additional reporting by Alvin Lum