A seven-judge bench led by Justice Nasir-ul-Mulk further directed the premier to submit a report giving details of the action taken by him at the next hearing on March 21.
The bench issued the directive while hearing a case regarding the implementation of its earlier order striking down a graft amnesty that had benefited President Asif Ali Zardari and over 8,000 others.
The bench said in its brief order that Gilani should write a letter to the Swiss authorities without waiting to seek the advice of his legal experts.
In the past, the premier has told the court that his legal advisors had informed him that the cases against Zardari could not be revived as the constitution provides immunity to the President.
The court asked Attorney General Anwar-ul-Haq to "immediately" convey its directive to Gilani. The same seven-judge bench also took up contempt proceedings initiated against Gilani for failing to act on the court`s orders to reopen cases against Zardari and asked the premier to record his detailed response by March 21, failing which final arguments would get underway.
The bench issued this direction after the Attorney General, the prosecutor for the contempt case, cross-examined Cabinet Secretary Nargis Sethi, who is appearing as a witness.
Emerging from the hearing, Gilani`s lawyer Aitzaz Ahsan told reporters that the bench had asked the premier to submit a detailed statement by March 19 or to appear in person and record his statement on March 21. "If he (Gilani) makes a statement, the final arguments will begin from March 21," Ahsan said.
The Supreme Court recently indicted Gilani for contempt of court after he refused to act on orders to reopen cases of alleged money laundering against Zardari in Switzerland.
The apex court has been pressuring the government to revive the cases since December 2009, when it struck down the National Reconciliation Ordinance, a graft amnesty issued by former military ruler Pervez Musharraf. The government has refused to act, saying the President enjoys complete immunity from prosecution within Pakistan and abroad.
Ahsan contended that the prosecution had not proved its case as it had only produced the Supreme Court`s past orders. "As long as a person is President, he cannot be pushed before a judge in a foreign country," he remarked. The premier was advised by officials that the cases against Zardari could not be reopened, he said.
Subsequently, Gilani wrote to officials that the Supreme Court should be taken into confidence on the government`s view but the court did not take up the matter for over a year, he said. "It was only in January 2012 that the Supreme Court took up the issue. People can sharpen their knives but we have genuinely proved our case. We have a good case," Ahsan said.
If convicted, 59-year-old Gilani could be jailed for six months and face the possibility of being disqualified.
In a separate case, a two-judge bench of the Supreme Court said former Law Minister Babar Awan, a confidant of Zardari, would be formally indicted for contempt of court on March 20.
Awan, who was recently appointed vice-president of the ruling Pakistan People`s Party, was issued a notice last year to explain why contempt proceedings should not be initiated against him for remarks he made about the judiciary during a news conference. The bench rejected Awan`s explanation and said he would now be indicted.