Last week, the party sent Mr Lawan’s name to INEC as the candidate for Yobe North, even though he was widely known not to have taken part in the primary.
The Senate on Tuesday announced Philip Aduda (PDP-FCT) as minority leader and Chukwuka Utazi (PDP-Enugu) as the minority whip.
Mr Amadi said the group was alarmed at the efforts of some politicians and party leaders to undermine the provisions of the electoral law.
Mr Lawan did not participate in the primary. Bashir Machina, who contested the primary and won, has been challenging the party’s determination to misappropriate his mandate.
The ruling party appeared to have relied on a clause that mandated primary contenders to withdraw from a race voluntarily or be arbitrarily substituted by the party.
Mr Abaribe’s resignation letter was read by the President of the Senate, Ahmad Lawan, during Wednesday’s plenary.
The APC Senator from Kebbi state resigned following his defection to the opposition Peoples Democratic Party (PDP).
Mr Machina said he scored 289 out of 300 votes cast by delegates at primaries and vowed not to cede his mandate to Mr Lawan or anyone else.
Smart politicians don’t do anything to call attention to a strength that can be a major political liability.
The PASAN chairman said he would communicate the outcome of the meeting to his other colleagues.
