Leader of Pakistan Tehrik-i-Insaf Imran Khan and religious scholar Tahir-ul Qadri have planned marches to Islamabad Aug 14, Xinhua reported.
Khan is demanding the resignation of the prime minister as he claims that last year's "elections were rigged" and that Sharif has been elected through a "fake mandate".
Qadri says he wants to bring about a revolution as the present system has "failed to deliver justice".
The two leaders have decided to jointly launch the march Thursday, the day coinciding with the country's Independence Day. They say the protestors will not leave Islamabad unless the prime minister resigns.
Imran Khan is demanding the resignation of the prime minister
The government has not yet decided to allow the marches and the authorities in Islamabad have started blocking some roads, the move indicating the government may not allow the marchers to enter the capital.
Special Assistant to the Prime Minister on National Affairs Irfan Siddiqui says the prime minister will take the nation into confidence on the current political situation.
Nawaz Sharif will also present a report on the government's performance before the nation. The fast growing political uncertainty has badly affected trading at the Karachi Stock Exchange (KSE).
The stock market on Tuesday morning was seen heading for another worst day as the benchmark KSE-100 index went sliding down by 500 points at the very outset of trading to peg at 27,564 points, local media reported.
On Monday, the KSE recorded the biggest ever single-day decline in terms of points as investors went on a panic selling drive following turbulence on the political front.
The business community in Islamabad is also worried over the possible confrontation and has moved the court against the marches.