Jharkhand Speaker Inder Singh Namdhari on Wednesday heard the disqualification petition against MLA Enos Ekka and reserved the judgement.
The petition against Ekka was filed in 2005 by Jharkhand Party (JP) president NE Horo accusing the MLA of flouting the party whip and joining the NDA government.
This was the third time the Speaker had heard the petition against the legislator, a former state minister.
"We have pleaded with the Speaker's court that we were given just two days' time to file replies and that the case was being taken hurriedly ahead of Thursday's confidence vote.
"We also requested the Speaker to deliver the judgement," RK Jain, counsel for Ekka, said.
Jain, a Supreme Court lawyer, told newspersons he had produced an affidavit signed by 13 of the 21-member executive committee of the JP.
These members had claimed there was neither any resolution passed by the JP on March 1, 2005, directing Ekka to vote for the UPA, nor authorising its President Horo to carry out the order, he said.
The Speaker is scheduled to take up two other disqualification petitions against NCP MLA Kamlesh Singh and Independent MLA Stephen Marandi later in the day.
While Singh faces the petition for allegedly flouting party whip last year, Marandi is facing charges of joining a political party after being elected as an independent.
The Arjun Munda government, reduced to a minority following resignation by four ministers, is facing a crucial floor test on Thursday.