Thursday's attack by Islamic State at Sufi Lal Shahbaz Qalandar in Sehwan town, some 200 kms northeast of Karachi, is one of the deadliest in the country.
A spokesperson of the Sindh health department said 67 bodies have been identified and handed over to their families.
"The death toll from the suicide attack stands at 80, including 20 children. Over 200 people who were inside the shrine were wounded and are being treated at hospitals in Sehwan, Nawabshah, Moro and Jamshoro," he said.
Faisal Edhi of Edhi foundation, a non-profit social welfare group, rushed to Sehwan for the rescue operations. He feared that the death toll could rise as some of the injured were still in critical condition.
Angry people took to the streets in Sehwan town to protest against the terrorist attack and failure of the government to provide proper security at the shrine where thousands of devotees gather every Thursday.
The mobs damaged vehicles and set a police van on fire and burnt tyres to block roads.
"There is only one scanner at the shrine for thousands of devotees who come to the shrine and even it was not working properly," a protester, who lost his brother and friends in the blast, told a television channel.
Relatives of the injured people complained about improper medical care facilities at the civil hospitals in Sehwan and Nawabshah.
Initial investigations said that there was no proper electricity at the shrine when the attack took place.
"Investigations point to the fact that the attacker came dressed in a Burqa and entered the shrine from the golden gate amidst the heavy crowd of devotees," DIG Hyderabad range Manzoor Rind said.
Hyderabad is the largest city closest to the town of Sehwan where the shrine was attacked. Rind said the CCTV footage at the shrine was being examined to identify the attacker.