Abbasi is expected to give way to outgoing leader’s brother Shahbaz, who plans to contest a parliamentary seat.
Pakistan’s former Prime Minister Nawaz Sharif has called for “a change and revolution” as he ended a four-day procession from Islamabad to Lahore.
Addressing tens of thousands of supporters in his party’s eastern stronghold on Saturday, Sharif criticised the Supreme Court for his removal, saying he would “not sit at home now” and would “change the fate of the country”.
His removal last month for concealing assets has plunged the nuclear-armed nation into political uncertainty.
On Wednesday, Sharif set off on a 370km journey in an armoured vehicle, in a display of street power against the court judgment.
Thousands came to catch a glimpse of the former leader as his convoy rolled down the Grand Trunk Road, a more than 2,000-year-old trade route which leads from Chittagong in Bangladesh across India and Pakistan to the Afghan capital Kabul.
Speaking at the famous Data Darbar, a well-known Sufi shrine, Sharif said that along his journey he saw that citizens had not accepted his disqualification. He asked his supporters to await his next move, without elaborating.
Citing his accomplishments, Sharif asked why a prime minister was disqualified when he was moving the country towards progress.
“This country belongs to 200 million people and not the few who ousted me, disrespecting your vote.”
“Who are those people who have disqualified me? Are they themselves qualified?” he asked the crowd, which responded with chants of “Prime Minister Nawaz Sharif”.
The rally in Lahore is expected to galvanise Sharif’s political base in advance of what he had earlier promised was the start of a “grand debate” on the military’s role in the running of the country.
Sharif has a rocky history with the country’s military establishment, which has ruled Pakistan for about half of its 70-year history.
He served three separate stints as premier but never completed a full term in office.
Within days of his removal, the Pakistan Muslim League-Nawaz (PML-N) nominated Shahid Khaqan Abbasi – former oil minister – as a new prime minister, with the National Assembly rubber-stamping the choice.
On Friday it was announced that Sharif’s wife, Kalsoom Nawaz, would contest the vacant parliamentary seat.