On Tuesday, police said about 30,000 security troops have fanned out around the parliament and the capital's high-security "Red Zone", which houses key buildings including parliament, the prime minister's house and numerous Western embassies, ahead of the planned mass anti-government rally.
The area has been cordoned off with shipping containers and heavily guarded by security personnel since the anti-government protests began in Islamabad five days ago.
Khan, the former Pakistan cricket captain and current leader of Pakistan Tehreek-e-Insaf (PTI) political party, said on Twitter on Tuesday that he himself would lead the march and reaffirmed his call for Sharif to resign.
Meanwhile, Canada-based outspoken cleric Tahir-ul-Qadri has said his followers would also march peacefully on Tuesday to try to force Pakistan’s incumbent prime minister to leave office.
The Pakistani government, in return, has begun efforts to find a negotiated resolution to the anti-government protests.
"Instead of the march, we request that Imran Khan and Tahir-ul-Qadri agree to talks with the government," a senior Cabinet minister, Ahsan Iqbal, said.
"Let us sit and find a political solution," Iqbal, who was appointed by Sharif to lead talks with the opposition, added.
Tens of thousands of people have descended on Islamabad in recent days, answering the call from Khan and Qadri to push for Sharif’s departure.
Both Khan and Qadri have left an offer of talks from Pakistani prime minister dangling. Khan has not responded to the government’s call for talks, seeking more details. However, Qadri has rejected the offer outright.
The two opposition leaders have called for Sharif to quit, accusing him of corruption and ballot rigging in last year's parliamentary election. The pair wants new elections to be held in Pakistan.
They vowed to keep up anti-government demonstrations until their demands are met and Sharif leaves office.