three-judge bench led by Chief Justice Iftikhar Chaudhry, National Accountability Bureau chairman Fasih Bokhari said investigators had not yet uncovered enough evidence to arrest Ashraf or any other suspects linked to alleged corruption in rental power projects.
The bench directed Bokhari to submit the complete record of investigations into the power projects and adjourned the matter till January 23.
Earlier in the day, the bench was irked when Bokhari said the evidence gathered so far was weak and unlikely to lead to convictions.
He also said an investigation report submitted to the apex court in the past was inaccurate.
Bokhari said the allegation about the power projects causing losses to the national exchequer had not been proved.
Investigation officers had worked in a hurry and did not provide adequate proof in their reports, he added.
His remarks angered the bench, which said the stand taken by NAB did not reflect the reality.
The Chief Justice directed Bokhari and other NAB officials to immediately submit all records of their investigations to the Supreme Court.
NAB prosecutor KK Agha argued the apex court could not see the agency's investigation records but the bench maintained that the documents should be submitted on Thursday.
NAB officials then said the records were with an official in Rawalpindi and would be submitted to the Supreme Court's Registrar later.
Chief Justice Chaudhry remarked that some persons involved in the rental power projects case seemed to think they were "above the law" and made it clear that the court was determined to take action in the matter.
On Tuesday, the apex court had directed NAB to arrest the premier and more than 20 other suspects in connection with alleged graft in the rental power projects.
Officials and federal ministers have already said the premier is unlikely to be arrested soon as several procedures will have to be completed before a warrant can be issued.
Legal experts have said the premier can continue to perform his duties as the chief executive even if he is arrested.
The graft charges against Ashraf date back to his tenure as Power Minister, when contracts were signed for several rental power projects as part of the Pakistan People's Party-led government's strategy to overcome a crippling energy shortage.
Though Ashraf was dropped during a cabinet reshuffle in 2011, he remained close to President Asif Ali Zardari.
The apex court began investigating the rental power plants in 2009 following a complaint of corruption from PML-Q parliamentarian Makhdoom Faisal Saleh Hayat.
The court had directed NAB to take action against all government functionaries involved in clearing the power projects, including ministers who held the power portfolio since 2006 and officials of state-run power utilities who derived financial benefits from the contracts.