The rival political parties have formally agreed to vote on next year's state budget bill in a plenary session scheduled for December 20.

The chief deputy floor leaders of the ruling People Power Party(PPP) and the main opposition Democratic Party(DP) signed a written agreement on Friday.

DP deputy floor leader Park Ju-min said the parties have also agreed to hold additional plenary sessions on December 28 and on January 9 to handle a lineup of pending bills.

While the parties have stated in the agreement that they will work to pass all pressing livelihood bills within the year, PPP deputy floor leader Lee Yang-soo said the January 9 plenary session was added to reflect the parties' resolve to pass the legislation.

The two sides differed, however, on the DP's push to handle a set of special counsel motions: one on stock manipulation allegations against First Lady Kim Keon-hee and another on the so-called "Five Billion Won Club” linked to the Daejang-dong development scandal.

The DP deputy floor leader said the bills will automatically be submitted on December 28 following a stay period, while his PPP counterpart urged the opposition to consider public sentiment and partisan relations.