Then-Ambassador to Australia Lee Jong-sup attends a defense cooperation meeting of ambassadors at the Ministry of Foreign Affairs in Seoul, Thursday. Yonhap

Korea's Ambassador to Australia Lee Jong-sup stepped down Friday amid a continuing controversy that his appointment was aimed at helping him sidestep an ongoing investigation into his alleged meddling in a probe into a Marine's death last year.

It is widely believed that he offered his resignation and the government and President Yoon Suk Yeol decided to accept it in consideration of the negative impact on the ruling bloc in the lead-up to the April 10 general elections.

But the resignation is also expected to draw criticism regarding Korea's diplomacy, as it came only 25 days after he was appointed to the post in a crucial partner country. It also came only 19 days after he left for Canberra and eight days after he returned to Korea to participate in a defense-related meeting of Korean envoys to six countries.

Lee offered his resignation to the minister of foreign affairs on Friday, and the ministry announced its decision to accept it, saying Lee strongly requested it.

In a statement issued by his lawyer, Lee urged the Corruption Investigation Office for High-ranking Officials (CIO) to question him as soon as possible over the allegations.

"I kept demanding the CIO to question me promptly, but it has yet to schedule a date for it," he said in the statement. "I will remain in Seoul after the defense meeting and cooperate actively with all investigation procedures."

Lee had been under the CIO's investigation over allegations that he interfered in the military's probe into the death of a Marine during a search-and-rescue operation amid heavy rain and massive flooding last summer when he was defense minister.

But he was appointed as ambassador to Australia on March 4, even though he had been under an overseas travel ban. After he went through a brief questioning by the CIO on March 7, the justice ministry lifted the ban the next day, and he flew to Australia on March 10.

The lifting of the travel ban caused controversy that the government allowed a key suspect in the probe to flee, and the opposition parties and civic groups even requested the CIO to investigate Yoon and the foreign and justice ministers for abusing their power to help a fleeing suspect.

As the issue grew and began to undermine support for the ruling bloc, even figures in the ruling People Power Party reportedly called for Lee's return to the country to face questioning or even resignation.

Following these calls, he returned to Korea on March 21, citing attendance at a major defense meeting of ambassadors as grounds, and said he would undergo questioning if the CIO summons him. But the hastily arranged meeting also brought criticism that the foreign ministry had acted to bring Lee back to Korea before the elections.

Regarding Lee's resignation, the Embassy of Australia in Seoul stated its intention to collaborate closely with the next appointed ambassador.

"Australia greatly values its relationship with the Republic of Korea, and looks forward to working in close cooperation with the next ROK ambassador to Australia across all areas of our comprehensive strategic partnership," the Australian Embassy in Seoul said in a statement provided to The Korea Times, Friday.