"Musharraf has to answer for his actions. Those actions constitute a treason case against him," Sharif, overthrown by Musharraf in 1999 in a bloodless military coup, told the National Assembly.
Attorney General Munir A. Malik told the Supreme Court on Monday that the government was consulting legal experts on initiating a treason case against the once supremely powerful ex-general.
The country's top court has been hearing petitions from several lawyers since April 6 requesting that it order the government to initiate a treason case against Musharraf.
Under Pakistani law, only the government can initiate treason charges, legal expert Babar Sattar said.
“If proven guilty, Musharraf could face the death sentence or life in prison,” Sattar told UPI Next.
Musharraf was head of the armed forces when he ousted Sharif’s previous government in October 1999 and sent Sharif and his family into exile. The general became president in 2002 and later quit the military.
During a standoff with the judiciary in November 2007, Musharraf imposed emergency rule and detained the chief justice of the Supreme Court, Iftikhar Muhammad Chaudhry, then the country's top judge, sparking epic nationwide protests by thousands of lawyers and judges.
Musharraf returned to Pakistan on March 24 from four years in self-exile, planning to contest last month's legislative elections. He was arrested on April 19 and since then has been under house arrest at his home on Islamabad's semi-rural outskirts.
He is also facing charges over failing to provide adequate security for former premier Benazir Bhutto when she returned from her own self-imposed exile in 2007 to contest the 2008 elections. Bhutto was killed as she departed an election rally in Rawalpindi, the city neighboring Islamabad, on December 27, 2007.
Sharif's resounding election last month as prime minister for a third term crowned an epic political comeback 14 years after he was deposed by Musharraf.
The move by a civilian government to try an ex-general for leading a coup is historic for Pakistan, which has seen three military coups in its 66-year history.