The party also called on INEC to conduct fresh elections within a stipulated time to fill the ''vacancies''.
The Peoples Democratic Party (PDP) has asked the speaker of the Rivers House of Assembly to declare vacant the seats of the 27 PDP lawmakers who defected to the All Progressives Congress (APC).
The 27 out of 31 lawmakers in the state assembly on Monday morning during plenary announced their defection to the APC, citing division within the PDP as the basis for their action.
In a statement on Monday evening, Debo Ologunagba, the national spokesperson of the PDP, demanded that the defected lawmakers vacate their seats.
Mr Ologunaba asserted that by defecting from the PDP, a political platform where the lawmakers were elected, their seats have become vacant.
''For the avoidance of doubt, Section 109 (1) of the 1999 Constitution provides that ''a member of a House of Assembly shall vacate his seat in the House if ... (g) being a person whose election to the House of Assembly was sponsored by a political Party, he becomes a member of another political party before the expiration of the period for which that House was elected...
''By reason of the above Constitutional provision and its clear interpretation by the Supreme Court, the 27 defected members of the Rivers State House of Assembly have vacated and lost their seats, rights, privileges, recognition and obligations accruable to members of the Rivers State House of Assembly,'' he said.
The PDP called on the Independent National Electoral Commission to conduct fresh elections within a stipulated time to fill the ''vacancies''.
''Our Party cautions that the former lawmakers should stop parading themselves as members of the Rivers State House of Assembly as such would amount to impersonation with serious criminal consequences,'' Mr Ologunagba said.
Rivers assembly has been enmeshed in a political crisis after some lawmakers began an impeachment proceeding against Governor Siminalayi Fubara in October.
As a result, the assembly has split into two factions - a faction backed by the former governor, Nyesom Wike, who is now the minister of the Federal Capital Territory and the second faction loyal to Governor Fubara.
Martin Amaewhule is the speaker of Mr Wike's faction while Edison Ehie, a former leader of the assembly who was removed for not supporting Governor Fubara's impeachment, is the speaker of the faction loyal to Mr Fubara.
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The two factions have repeatedly held parallel sittings at different locations in Port Harcourt.
The political crisis has worsened despite President Bola Tinubu's intervention.
The two factions reportedly held parallel sittings on Monday under heavy security mounted by the police after which Mr Wike-backed faction announced their defection to the APC.
Meanwhile, the APC in Rivers State has welcomed the defected lawmakers, describing their action as a welcome development.
The spokesperson for the state caretaker committee of the party, Chibuike Ikenga, told Punch newspaper on Monday the state will be effectively governed by the number of lawmakers who defected to the party.
