A Seoul court questioned a prosecutor Tuesday to determine whether to issue an arrest warrant for him over allegations he conspired with the main opposition party to investigate pro-government figures when opposition presidential contender Yoon Seok-youl was in office as prosecutor general.

The Corruption Investigation Office for High-ranking Officials (CIO) sought the warrant for Son Jun-sung on charges of asking a prosecutor-turned-lawmaker of the main opposition People Power Party to file complaints against key ruling camp officials last year.

"I will thoroughly explain to the judge the unfairness of the arrest warrant request," Son told reporters as he arrived at the Seoul Central District Court.

The CIO said it has repeatedly asked Son to appear for questioning but he has been uncooperative, offering "unconvincing reasons" for rejecting the summon requests.

Investigators in charge of the case reportedly confirmed Son's involvement after a team analyzed a massive trove of digital data and documents obtained from a whistleblower and the SPO.

Son's arrest, if approved, would be a blow to Yoon.

The CIO has booked Yoon on multiple charges, including abuse of power, in its probe into the scandal.

Yoon has denied involvement in the case. His campaign has criticized the CIO move as political maneuvering to undermine support for Yoon ahead of the PPP primary. (Yonhap)