The leader of an influential Pakistan political party has called for better state-provided security after a Daesh suicide bomber killed 54 people, almost half of them children, at an election gathering.

Jamiat Ulema-e-Islam-F (JUI-F)'s leader, cleric Fazlur Rehman, on Tuesday questioned how such a "significant intelligence failure" could have occurred.

Around 400 members of the JUI-F party, a key government coalition partner, were meeting on Sunday when a bomber detonated a vest packed with explosives and ball bearings.

"The entire nation is turning to the state institutions responsible for its security," he said in a statement posted to Twitter.

"Where are they? When will they listen to us? When will they heal our wounds? When will they establish a system that safeguards our future generations?"

Rehman said Jamiat Ulama-e-Islam was a peaceful party, "but even patience and endurance have their limits".

"Nonetheless, I urge my supporters not to abandon patience and endurance," he said.

Rising militancy

Sunday's attack occurred in the town of Khar, 45 kilometres (28 miles) from the Afghan border, in an area where militancy has been rising.

The blast has raised fears Pakistan could be in for a bloody election period following months of political chaos prompted by the ousting of Imran Khan as prime minister in April last year.

Parliament is likely to be dissolved after it completes its term in the next two weeks, with national elections to be held by mid-November.

Terrorist assaults have focused on regions abutting Afghanistan, and Islamabad alleges some are being planned on Afghan soil — a charge Kabul denies.