Police carried out operations in several parts of Lahore on Thursday, detaining more than 300 Pakistan Tehreek-e-Insaf workers ahead of a planned rally in Islamabad, according to the report.
Police officials said the arrests were made over fears of possible law and order disturbances. Lists of active party workers were prepared, and door to door checks were conducted in different neighbourhoods.
Authorities also documented details of individuals who managed to avoid arrest and went into hiding, while efforts are underway to trace the whereabouts of those still being sought.
Police said legal cases will be filed against anyone involved in violent protests or attempts to disrupt public order.