Davos:  Maintaining that Pakistan President Asif Ali Zardari enjoys complete immunity, Prime Minister Yousuf Raza Gilani says he is ready to go to prison if the court desires.

"That is the old case which has been pending since a long time for which the President has already completed about eight years in prison and now as the president of the country he has complete immunity," Gilani said here when asked about the charges against him.

Gilani, who is attending the World Economic Summit being held here, said in an interview with television channel on Friday that the Court wanted a letter sent to the Swiss courts, to "which we said that according to the Constitution he (the president) has a complete immunity not only inside Pakistan, but also transnational immunity not only for the President, the Prime Minister and even the Foreign Minister".

Asked if he expects to go to prison, Gilani said, "If the court so desires, I have no objection".

Gilani has been facing the Pakistani Supreme Court's ire for failing to reopen graft cases against Zardari.

He was even forced to appear in person before the Apex Court after he was issued a contempt notice.

The Supreme Court has been pressuring the Pakistan People's Party-led government to reopen the cases against the President in Switzerland since it struck down a graft amnesty that benefited Zardari and over 8,000 others in December 2009.

It has declared that the National Reconciliation Ordinance, the graft amnesty issued by former military ruler Pervez Musharraf in 2007, was unconstitutional and illegal.

Meanwhile, Gilani also said Musharraf will "certainly" be arrested if he returns to Pakistan.

"In fact there had been murder charges against him, and there had even been some very grave charges against him, and the Supreme Court had already given a verdict against him," Gilani said.

"Certainly when he'll come back, he has to face those charges and certainly be arrested," he said.