Although Prime Minister Nawaz Sharif has been ousted from the top office by the Supreme Court, as the head of the ruling Pakistan Muslim League-Nawaz (PML-N) party he will be able to nominate his successor.
The judges on the bench unanimously ruled that the Pakistani prime minister had been dishonest to the Parliament and the courts, and that he could not be deemed fit to hold office.
To assume the post of prime minister, Shahbaz Sharif needs approval from parliament, but PML-N has a comfortable majority in the 342-seat house.
If the parliamentary party validates the decision, Shahbaz will have to resign from the Punjab Assembly and a new provincial Chief Minister will have to be chosen.
Supporters of the PTI opposition party who had gathered outside the court and who jeered politicians from Mr Sharif's party shouted: "Go, Nawaz, Go".
If Shahbaz Sharif, 65, is to take over, he must quit as governor of Punjab province and then win a by-election into parliament, which should take 45 days.
On Friday, Sharif was forced to step down following a Supreme Court ruling that deemed him disqualified over corruption charges.
The court also directed the country's anti-corruption authorities to file separate corruption cases against the former prime minister, the finance minister, his two sons, daughter, and son-in-law for their involvement in the Panama Papers scandal.
Shahbaz Sharif, now the chief minister of Punjab province, which is Pakistan's most populous region and the Sharif's political heartland, will have to resign from that post and run for a by-election to join parliament before he is elected as prime minister.
In 2016, Icelandic Prime Minister Sigmundur David Gunnlaugsson stepped down amid public outrage that his family had sheltered money offshore.
The rally came a day after Pakistan's Supreme Court removed Sharif from office after finding that he and his family concealed their assets.
This is the third time 67-year-old Nawaz Sharif's term as premier has been cut short. But Ali Ibn-e-Khalid has asked, "Why not shahid khaqan Abbasi till next election why they cant let it go out of one family can you explain is this democracy".
Sharif resigned Friday, saying he had reservations about the court ruling. After PML-N victory in 2013 general elections, he was made a part of federal cabinet by allotting him the Ministry of Petroleum and Natural Resources. In 1993, he was ousted after a bitter struggle with the country's president, and in 1999 the military overthrew him in a bloodless coup.