Thilanga Sumathipala says he is prepared to step down as general secretary of the UPFA only if Mahinda Amaraweera withdraws the petition against his appointment.
Sumathipala has intimated to party chairman Maithripala Sirisena of his stand in a letter dated 31 January.
He refuted reports that he tendered his resignation.
Amaraweera was replaced by Sumathipala in the position after the former went against a party decision and joined the government with a ministerial position.
He then filed a case in the Colombo district court, naming Sumathipala as a respondent.