Rescue officials said the accident occurred when a bus was in collision with a container truck at about 5.40 am (0040 GMT) in Dera Ghazi Khan district 466 km (289 miles) south-east of Lahore.
The injured and dead were taken to a nearby hospital by the rescue service.
"As many as 30 people have died and 74 have been wounded," Dr Najeebur Rehman, Medical Superintended of Dera Ghazi Khan Teaching Hospital, told Reuters, adding the toll might rise as several injured are in serious condition.
Fatal road accidents are common in Pakistan, where traffic rules are rarely followed and roads in many rural areas are in poor condition.
Last month, a train crash killed 56 people in Sindh province and left dozens wounded.
Pakistan information minister Fawad Chaudhry expressed sorrow over the loss of life in Monday's accident.