The nation's top court on Wednesday accepted the resignation of a senior judge for delivering a controversial ruling that valued a convicted former tycoon's prison labor at 500 million won ($467,726) a day.

Chang Byong-woo, the chief of the Gwangju District Court in the southwestern city of Gwangju, offered to resign on Saturday, holding himself accountable for allowing Huh Jae-hoh, the former chairman of the now-defunct Daeju Group, to pay off his fines of 25.4 billion won through 50 days of manual labor at a prison facility.

The rate applied to the 71-year-old property mogul, who is convicted of tax evasion and embezzlement, was up to 10,000 times higher than the normal daily wage of an inmate, generally valued at between 50,000 won and 100,000 won per day. The local media here have called it "the emperor's labor."

Adding to the controversies, allegations have risen about a dubious real estate transaction between a construction subsidiary of the former chairman's business empire and the embattled judge, whose entire bench career had been limited to Gwangju.

"There was no concrete evidence backing up that judge Chang had committed illegal acts related to his duty," the Supreme Court said in a statement, adding the statute of limitations for the 2008 transaction had expired as well.

The court's decision, however, is likely to stir more criticism for allowing the senior judge to retire without conducting a proper investigation into various allegations.

After controversies erupted, prosecutors last month released Huh from a prison labor facility, vowing to levy the remaining 22.4 billion won in fines after deducting six days of prison labor.

The top prosecution office and tax authorities also have begun looking for his assets, believed to be hidden in New Zealand, where he had maintained an extravagant lifestyle as a fugitive.

Also, the Supreme Court set up general guidelines in the current prison labor system and vowed to further discuss ways to improve it amid harsh criticism that a wealthy chief executive had exploited legal loopholes to dodge levied fines.

Daeju, a former business group based in Gwangju with 15 subsidiaries, collapsed in 2010 when its main construction arm went bankrupt due to a slump in the property market. (Yonhap)