Lawmakers on Tuesday stepped up their attacks on President Park Geun-hye's nominee for Constitutional Court chief as they tried to determine whether he is ethically fit for the job.

Park Han-cheol, who was tapped by the president last month to head the top court, faced a barrage of questions from lawmakers over whether the large legal fees he received at a law firm in 2010 were justified.

Park, a former public prosecutor, is known to have earned a total of 245 million won (US$215,000) during the four months he worked for the law firm Kim and Chang following his retirement from the prosecution.

Lawmakers have raised allegations that he received "jeon-gwan-ye-u," a practice believed to be widespread in South Korea whereby former senior officials, including prosecutors and judges, use their connections with their incumbent former colleagues to get preferential treatment at the private firms they join after retirement.

On Tuesday, the second day of Park's parliamentary confirmation hearing, the main opposition Democratic United Party demanded to see the nominee's contract with the law firm, but Park claimed that he did not have a copy, while the law firm declined to hand it over, citing internal policy.

"If so, what was the money Park received -- a reward for his investments (in the company), legal fees or a salary?" Rep. Lee Che-ik of the ruling Saenuri Party asked during the hearing.

"Rather than claiming it is a business secret, this should be an opportunity to lay it out in the open."

The nominee said he "slightly regrets" that he joined a law firm after retirement, and apologized once again for causing controversy over his alleged links to "jeon-gwan-ye-u."

Park also apologized on Monday and promised not to return to the law firm if he retires from the Constitutional Court.

Lawmakers will decide Wednesday whether to adopt a report on the hearing. If it is adopted, Park's nomination will be put to a vote at a full National Assembly session scheduled for Thursday.

If he fails to win parliamentary approval, it could deal another blow to the president who has already been plagued by a series of unsuccessful nominations for senior government posts.

By law, the president can still appoint a nominee without parliamentary approval.

Park named the former prosecutor after her predecessor Lee Myung-bak's pick for the job, former Constitutional Court justice Lee Dong-heub, resigned in February under pressure over allegations of a series of ethical lapses, including tax evasion and speculative real estate investment.

The new president took office on Feb. 25.

(Yonhap News)