The former No. 1 and No. 2 officials of the national tax agency were indicted Tuesday on charges of accepting bribes worth about 300 million won (US$268,000) from food and entertainment conglomerate CJ Group while in office, prosecutors said.

Jeon Goon-pyo, 59, is accused of taking US$300,000 in U.S. bills from CJ Group officials in exchange for favors during a tax audit into the conglomerate in July 2006, shortly after he was named the commissioner of the National Tax Service (NTS), they said.

Jeon, who has been locked up since earlier this month shortly after a Seoul court approved the prosecution's request for an arrest warrant, allegedly conspired with Heo Byung-ik, the NTS deputy commissioner at the time, they added.

The Seoul Central District Prosecutors' Office said Jeon is further accused of accepting a high-end watch worth 35 million won from CJ Chairman Lee Jay-hyun as an inauguration gift at a Seoul hotel in October 2006.

During the prosecution's questioning, Jeon and Heo both admitted to accepting the kickbacks from CJ Group while denying they were in exchange for any favors, prosecutors said.

The prosecution office said it has charged Heo, who is also behind bars pending trial, with conspiracy to aid and abet the receipt of bribes, judging that he just delivered the money from CJ officials to Jeon.

A bribery scandal involving former top tax officials came into light after chairman Lee was indicted for embezzlement and offshore tax evasion charges in a separate corruption case last month.

During the audit into CJ Group in 2006, tax authorities obtained evidence that the group and its chairman allegedly dodged some 356 billion won in corporate and income taxes. However, the NTS neither collected nor levied any fines on the family-run conglomerate, according to prosecution sources.

The prosecution office suspects that CJ group and Lee illegally lobbied the former NTS officials so that the conglomerate could reduce its tax burden or even avoid paying the massive amount of taxes altogether.

It is not the first time that Jeon was embroiled in similar graft scandals.

In 2008, Jeon was found guilty of taking some 60 million won from the former head of the Busan Regional Tax Office, Jung Sang-gon, in exchange for promoting him.

Three years later, Jeon underwent a separate prosecution probe on charges of receiving a high-priced painting from a senior NTS official in exchange for promoting him to the agency's No. 2 post.

Upholding a lower court's ruling, a Seoul appeals court acquitted Jeon of the second charge in August 2012. (Yonhap News)