The law gave parties the power to unseat lawmakers.
A bill to repeal the anti-defection law was proposed by PPM deputy leader Riyaz Rasheed.
The Supreme Court concluded hearings Tuesday to decide whether it will hear the opposition's challenge to the constitutionality of two controversial bills ratified last week.
The ruling party has proposed an anti-defection law to penalise floor crossing and strip lawmakers of their seats for switching parties.
