Eight PDP lawmakers, including the Speaker, Mr Collins Chiji, defected to APC on Tuesday.
According to him, the seats being occupied by the defected lawmakers belong to PDP not individuals.
Ozirim said that the PDP must move to reclaim its seats, in line with the provisions of the Constitution.
He explained that a lawmaker could only defect to another party if there was division or crisis in the party.
“There is no division or crisis in PDP; we will approach the Independent National Electoral Commission (INEC), to declare their seats vacant,” he said.