Home Affairs Minister Chong Jong-sup offered to resign Sunday, indicating he may run in the general elections in April.
Media speculation has continued over his political ambition.
The former law professor said he made the decision in order to not burden state affairs.
He left the door open to seeking a parliamentary seat.
"I will decide prudently after listening to the opinions of many people," Chong said.
He is expected to continue the ministerial work until his successor is chosen.
Last month, President Park Geun-hye replaced transport and maritime ministers who are widely expected to run in the elections on April 13.
Under South Korea's election law, civil servants aspiring for political positions should resign from their jobs at least 90 days before an election date.
Park is likely to carry out another round of partial Cabinet reshuffles this week that will affect a few other ministers with political aspirations.
"As far as I know, chances are high that President Park will carry out the cabinet shake-up for ministers with the intention of running in the general elections ahead of her upcoming overseas trip," an informed political source said.
Park will leave for Turkey, the Philippines and Malaysia to attend a series of multilateral summit meetings.
There have been media reports that Education Minister Hwang Woo-yea, Gender Equality Minister Kim Hee-jung and Trade Minister Yoon Sang-jick will likely be included in a Cabinet reshuffle. (Yonhap)
