Speaking in Islamabad at a time of growing tensions between Pakistan's powerful military and the civilian regime, Prime Minister Syed Yousuf Raza Gilani said "conspiracies are being hatched to pack up the elected government."
Later, he told the National Assembly there "cannot be a state within a state" and that all are answerable to Parliament.
Gilani's government, led by President Asif Ali Zardari, is trying to clear its name from a scandal relating to a memo allegedly seeking U.S. help to rein in the Pakistani military and prevent a possible coup. The government has denied any involvement in the scandal, which led to the resignation of Pakistan's ambassador to the United States.
The scandal has worsened Pakistan's relations with the United States, which were already strained after the May 2 killing of al-Qaida leader Osama bin Laden by U.S. forces in Pakistan's garrison town of Abbottabad.
The New York Times reported Pakistani army chief, Gen. Ashfaq Parvez Kayani, and Lt. Gen. Ahmad Shuja Pasha, head of country's spy agency, have asked the Pakistani Supreme Court investigate the memo.
The BBC said Gilani's strong words are seen as an unprecedented attack by a civilian leader against the military.
"But we will continue to fight for the rights of people of Pakistan whether or not we remain in the government," he was quoted as saying.
Zardari returned to Islamabad this week after seeking medical treatment in Dubai, amid speculation he might be forced out of office.
Pakistan's Daily Times said Gilani called Zardari as reports of a civilian-military confrontation on the political horizon were spreading. Details of their meeting were not disclosed.
The Wall Street Journal said the latest developments and Gilani's decision to get parliamentary approval for all policies could delay Pakistan's reopening of the supply routes for NATO forces in Afghanistan. The routes were closed after the Nov. 26 NATO airstrike along the border in which 24 Pakistani soldiers died.