Gilani made the remarks during a meeting with a group of ministers and parliamentarians that called on him this evening, said a statement issued by the premier`s office.
He said it was the Pakistan People`s Party government led by late Prime Minister Zulfiqar Ali Bhutto that introduced the blasphemy law.
"Therefore any amendment in this law would be against our party line," Gilani said.
Punjab Governor Salmaan Taseer, a senior PPP leader, was assassinated earlier this month by a police guard who said he was angered by the politician`s opposition to the blasphemy law.
Religious hardliners and opposition political parties have stepped up pressure on the government not to amend or repeal the controversial law.
Gilani said his government believes in taking all political partners on board while deciding national issues.
The government is pursuing a policy of political reconciliation and dialogue to solve the problems confronting the country.