Despite a request from minister of state for water Chaudhry Abid Sher Ali, the opposition refused to enter the Senate or upper house of parliament and chanted "Shame, shame, shame".
The opposition lawmakers said they would discuss a 10-point agenda during their "session" outside parliament, including interior minister Chaudhry Nisar Ali Khan's "attitude", a power tariff hike, inflation and the law and order situation in the financial hub of Karachi.
"The ( casualty) figures submitted by the interior minister were incorrect and were justifying the drone attacks conducted by the US," Pakistan People's Party (PPP) lawmaker Raza Rabbani said.
The interior minister recently said 2,160 militants and only 67 civilians were killed in US drone strikes. However, the figures were contested by opposition parties and rights groups.
Even the defence ministry told the media that these figures were wrong, Rabbani claimed.
"The records should be corrected immediately and the interior minister should withdraw figures pertaining to casualties in terrorist activities that he had presented in the upper house," Rabbani demanded.
He said the opposition did not have any other way but to hold a session outside parliament.
Meanwhile, leader of the house Raja Zafrul Haq, a senior leader of the ruling PML-N, informed the Senate about progress being made by a parliamentary committee to reconcile with the opposition.
He said the committee held two meetings with opposition members but they decided to carry on with their protest. The treasury benches are making efforts to bring the opposition back to the Senate and something positive will hopefully emerge from the meetings, he added.