Ruling Democratic Party Chairman Lee Nak-yon said Friday he will ask President Moon Jae-in "at an appropriate time" to grant pardons to two former conservative presidents imprisoned for corruption charges.

Lee, who served as prime minister under the Moon administration, made the remarks during an interview with Yonhap News Agency, also stressing that the party should play an active role in pushing for the matter in order to promote national unity.

As this year will be effectively the last year that President Moon can work, I thought that the issue should be dealt with at an appropriate time," Lee said. "Going forward, the party should play a more active role."

Former President Lee Myung-bak, who governed the country from 2008-2013, is serving a 17-year prison term after being convicted of corruption, while his successor Park Geun-hye is serving a 20-year prison term after being impeached over a far-reaching corruption and influence-peddling scandal. (Yonhap)