No one was injured by the blast that occurred before dawn on Thursday at the Pir Koh gas field in southwestern Baluchistan province.
Abdul Samad Lasi, a local official, said the explosion ruptured a pipe, 40cm in diameter, connecting a well to a compressor plant, disrupting supply to several cities in eastern Pakistan.
Multan, Bahawalpur and Faisalabad were among the places affected in the eastern Punjab province.
No one claimed responsibility. Authorities suspect local tribesmen who have attacked gas fields and security forces in a campaign for increased royalty payments from natural resources that are extracted from their territories.
Lasi could not say when the pipeline would be repaired.
Land mines near the pipe will need to be cleared before workers can go to the site to begin repair work.
Lasi blamed tribesmen for planting the land mines to stop security patrols in the area.