The Supreme Court asked the Election Commission of India on Monday to justify why it is reluctant to increase the number of vote confirmation slips, stressing that it doesn't mean to cast aspersions on the electronic voting machines.

At present, the poll panel counts verifiable paper audit trail (VVPAT) slips from one EVM in each assembly segment in Lok Sabha elections.

A bench of Chief Justice Ranjan Gogoi and Justice Deepak Gupta asked the Commission to explain by Thursday its reservation over extending the verification process to more EVMs. The SC said it could pass necessary orders on the next hearing on April 1 if the EC doesn't agree on its own.

The court was hearing a petition by 21 opposition parties demanding counting of minimum 50 per cent VVPAT slips per constituency.

Responding to EC's argument that its house was in order and any change will only cast aspersion on the efficiency of EVMs, which has remained a bone of contention between the Opposition and the poll panel, the SC said not "aspersion" but "satisfaction" must be met.

"No institution should insulate itself from improvement. There is room for constant improvement...if a Parliament constituency has 1,000 polling stations physical count of paper trails will be of one machine in assembly segment. So if a segment has 600 machines, you will check six. Can you do it for more on your own? Only if you have difficulties, we will consider passing orders."

EC's Deputy Secretary Sudeep Jain told the Court that the Commission has employed services of expert agencies for reforming the system. The verification of slips from one machine per constituency has not shown any variance and thus there is no reason to doubt our machines.

This became the flashpoint for the Court to remark saying that if the Commission was so confident of improving its system, why Court's orders were required to roll out 100 per cent VVPAT in all EVMs. "If you are so confident why didn't you bring complete VVPAT on your own? And even when the Court was considering it, how much opposition we faced from EC which said it is totally unnecessary. Yet we did it."

Hinting at a similar exercise to be repeated, the bench told EC to state on affidavit the difficulties likely to arise if more EVMs are to be verified. Senior advocate Abhishek Manu Singhvi who represented the 21 parties led by Andhra Pradesh Chief Minister N Chandrababu Naidu, informed the Court that the only difference will be that result declaration will delay by few hours.