The suit was instituted on July 2018 by an advocacy body known as Legal Defence and Assistant Project (LEPAD), NAN reports.
LEPAD is seeking the court to declare the seat of the affected national legislators vacant over their defection to the All Progressives Congress (APC) and the Peoples Democratic Party (PDP.
The lawmakers include Sen. President Bukola Saraki and the Speaker of the House of Representatives, Yakubu Dogara, among others.
Akpabio, who was granted leave by the court on Tuesday to personally challenge the suit, asked for the dismissal of the suit through his counsel Mr Sunday Ameh, SAN.
Ameh argued that LEPAD was not a political party or member of the National Assembly and as such, could not cry for the political parties where the law makers decamped from.
Akpabio who tendered two exhibits, told the court that his exit from the Peoples Democratic Party (PDP) was because he was suspended, right from his immediate ward.
He said he was later expelled from the same PDP at the local government level.
The Senate Minority Leader added that in line with the provisions of section 40 of the 1999 constitution, he opted for the All Progressives Congress (APC), as an alternative party.
Apparently justifying his move to the PDP, Akpabio, who is the third defendant in the suit, told the court that an uncommon situation was imposed on him before he left the party.
He said he was thrown out of the PDP by officials of the party, pleading with the court to take judicial notice of the two letters of July and August 2018 from the PDP.
According to Akpabio, his suspension and subsequent expulsion from the PDP was conveyed by the two letters.
He urged the court to accept the fact that he did not willingly decamp or abandon the party which sponsored him in 2015 senatorial election, but due to the action of the officials.
He further told the court he joined the APC in order not to become a political orphan and to actualize his political ambition.
“In order not to fall prey to the political gang up and to avoid being turned into a political orphan, I took advantage of my right in section 40 of the 1999 constitution.
“I joined the APC that was willing to accept me after PDP had thrown me out,’’ he said.
Counsel to Saraki, Mr Mahmoud Magaji (SAN), insisted in his argument that the suit was an abuse of court processes because of the provision of section 40 of the 1999 constitution.
Magaji told the court that the section allows the defendants to associate with the political parties of their choice.
Justice Okon Abang adjourned judgment until May 17