Ruling party leader Han Dong-hoon urged law enforcement Sunday to summon the ambassador to Australia home amid the ongoing investigation into his alleged interference in a military probe into the death of a Marine.

Han Dong-hoon, the interim leader of the ruling People Power Party, made the remarks as criticism is growing over the controversial departure of Ambassador Lee Jong-sup to the host country last week despite him being a subject in the investigation.

"The Corruption Investigation Office for High-ranking Officials has to subpoena (Lee) immediately and the ambassador has to return immediately," Han told reporters at the party's headquarters in western Seoul.

"I don't think it's an issue over which we should engage in political bickering ahead of the elections and cause distress to the people."

Lee, a former defense minister, is suspected of exerting undue influence in the Marines' internal probe into the death of Cpl. Chae Su-geun, who died last July during a search mission amid heavy rains.

Critics say that Lee's appointment and letting him leave the country to take up the top envoy post amount to helping a suspect flee overseas.

The issue is increasingly drawing attention weeks before the April general elections.