Islamabad: Prime Minister Yousuf Raza Gilani is not an honest man as he had not lived up to his constitutional oath, Pakistan's Supreme Court said on Tuesday. It also warned of action against him for failing to act on an order to reopen graft cases against President Asif Ali Zardari.

Piling pressure on PPP-led beleaguered government, a five-judge bench, which had taken up the issue of implementing the apex court's verdict striking down a graft amnesty that benefited Zardari, said in its order that Gilani was not an "honourable man" as he had not lived up to his constitutional oath.

The premier had shown loyalty to his political party rather than the Constitution, the bench said.

"Prima facie, the Prime Minister is not an honest man and violated his oath," the bench said in its order.

The bench contended that the Pakistan People's Party-led government's refusal to write a letter to Swiss authorities to reopen cases of alleged money laundering against Zardari went against the Constitution and the Quran.

The bench listed six options for the government, including action against the premier for contempt of court and declaring Gilani ineligible to be a member of Parliament for five years – and referred the case to Chief Justice Iftikhar Gilani. The bench recommended that the Chief Justice form a larger bench to hear the matter on January 16.

The bench asked Attorney General Anwar-ul-Haq to ascertain the government's views before the next hearing.

It also summoned the Attorney General, the Law Secretary and the chairman of the National Accountability Bureau to appear before the apex court at the next hearing.