Prosecutors on Wednesday summoned an incumbent judge over allegations he received kickbacks from a local businessman who is at the center of a lobbying scandal that is rocking the country's legal sector.

The Seoul Central District Prosecutors' Office said it called in the judge, identified only by his surname Kim, to ask questions over suspicions that he bought a used car owned by Jung Woon-ho, former chief of local cosmetics brand Nature Republic, at a below market price, and even got back some of the money from the purchase in 2014.

Kim is also suspected of traveling to Vietnam with Jung, with the businessman paying most of the travel expenses, according to prosecutors. 

Last year, Kim delivered a sentence, heavier than a lower court, to a defendant who was indicted for selling fake products of Nature Republic.

Prosecutors said they will grill Kim on why he did not ask for reapportionment on three cases that involved the cosmetic firm, despite his close relations with Jung.

After the allegations were raised, Kim asked for a leave of absence earlier this month and the country's top court allowed it till February.

A number of former and current legal professionals and businessmen are standing trial in relation to the sprawling scandal.

Jung himself has also been held in detention as prosecutors sped up their investigation. He was already behind bars after being convicted of illegal gambling earlier this year when a local court issued a warrant to arrest him in June on another set of corruption allegations. (Yonhap)