Main opposition Democratic Party(DP) leader Lee Jae-myung will not attend Thursday's plenary session, where a vote will be cast on parliamentary consent for his pretrial detention on corruption and third-party bribery charges.

The DP said Lee will not explain his position or issue a statement ahead of the vote, with a party official adding that his social media posting on Wednesday can be substituted as an expression of his position.

On social media, Lee urged party representatives to vote down the request, saying that the passage of what he called an "unlawful and unjust" motion would "give wings" to the prosecution's politically motivated investigation.

Ahead of Thursday's vote, DP floor leader Park Kwang-on visited Lee at a hospital in Seoul where his health has been monitored in an attempt to persuade the party chief to end the hunger strike on its 22nd day. Park said the two did not talk about the impending vote.