Religious groups have been staging protests in Islamabad for nearly two weeks.
The protesters have formed a sit-in at the Faizabad Interchange, causing disruption for many of the city's residents.
They are calling for the resignation of Law Minister Zahid Hamid, who they claim is behind the now-withdrawn change in a declaration for candidates, with the wording altered from "I solemnly swear" to "I believe".
However, the change, which has since been rectified, has been explained as a clerical error.
The interior minister has said he could not ask Hamid to resign without solid evidence against him.