The presidential office is looking into allegations that one of its staffers was involved in the leak of personal information concerning a child suspected to be the illegitimate son of former Prosecutor General Chae Dong-wook, an official said Tuesday.

A local newspaper has reported that the staffer allegedly asked a senior official at the Seocho-gu office in June to verify the resident registration number and other personal information of the child. He then sent a mobile phone message to the district official to thank him for his cooperation.

The staffer is reportedly denying the allegations.

"I heard the office of the senior civil affairs secretary is trying to determine what happened," senior presidential press secretary Lee Jung-hyun told reporters. He declined to discuss the matter in detail.

Chae resigned in September over allegations he fathered a son through an extramarital affair.

Chae denied the allegations, and the case was one of the hottest political issues at the time amid opposition suspicions the government engineered his removal because he had pursued an investigation too aggressively into the alleged state tampering in last year's presidential race. (Yonhap News)