Supreme Court had ordered the federal government to appoint a new Chief Election commissioner by October 28.
Khursheed Shah, in his reply, said that the office of the CEC is constitutional.
He added that the constitution makes it necessary for the Prime Minister and the opposition leader to appoint the commissioner after consultation but meaningful consultation will take time.
The opposition leader pleaded to the court to grant three months period for appointment of a new CEC.
It should be noted that the position is lying vacant since former CEC Fakhruddin G. Ebrahim resigned from office after being blamed of rigging during the general elections in 2013.