The bill, which reverses constitutional changes adopted by former military ruler General Pervez Musharraf, is likely to be passed in the house by a two-third majority, which is required to convert it into law.
Some of the major proposals mentioned under the constitutional reforms package includes the transfer of power from the Presidency to the Prime Minister's House, which means that the President would no longer have the power to dismiss the prime minister, dissolve parliament or appoint the head of the country's armed forces.
The 18th amendment would remove the bar on prime ministers standing for only two terms in office, which allows opposition leader Nawaz Sharif, who was dethroned by Musharraf in 1999, to contest for premiership for the third time.
Addressing Parliament after presenting the bill, Prime Minister Yousuf Raza Gilani said the constitutional amendments would actually strengthen institutions, rather than just making the Prime Minister more powerful.
"I congratulate the entire nation on this 18th amendment.It is historic. Some people think that the prime minister will be stronger now. But in fact these constitutional amendments will strengthen institutions. This is unprecedented in the history of Pakistan," The Dawn quoted Gilani, as saying.
"This is a bill which will ensure parliamentary supremacy," said Senator Raza Rabbani, the head of the parliamentary committee on constitutional reforms. (ANI)