"The ISI (Inter-Services Intelligence)... is an extremely important (and) sensitive institution of this country. If they do not agree to go to the American court, then no one can send them," Gilani said.
His remarks came as media reports from New York said the plaintiffs in two US lawsuits accusing Pakistan's spy chief of nurturing terrorists involved in the 2008 Mumbai attacks are hoping for a historic outcome recalling the Lockerbie settlement.
The lawyers of the victims said they hope to win a deal like the one struck with Libya over the 1988 bombing of the Pan Am flight 103 over Lockerbie, Scotland. The plaintiffs in that case won a USD 1.5 billion settlement.
The Pakistan Prime Minister was responding to concerns expressed by lawmakers in the National Assembly or lower house of parliament about the lawsuit filed by the family of two Jewish victims of the Mumbai incident.
He described the country's spy agency as an "extremely important" organisation.
Earlier, Leader of Opposition Chaudhry Nisar Ali Khan described the summoning of the ISI chief by the American court as an attack on Pakistan's honour.
He said the Prime Minister should send a Pakistani official to the US court to register a protest and Foreign Office should clarify its stand on the matter.
The court in Brooklyn has summoned current ISI chiefs Lt Gen Pasha and his predecessor Nadeem Taj and Lashker-e-Taiba leaders, including Hafiz Saeed, to appear before it next month in connection with the suit filed by relatives of Rabbi Gavriel Noach Holtzberg and his wife, who were among the 166 people killed during the attacks.
The lawsuit alleges that the ISI "provided critical planning, material support, control and coordination for the attacks" to the Pakistan-based LeT.
Indian officials have blamed the LeT for carrying out the attacks and said elements of the ISI and Pakistan Army played a role in planning and facilitating the assault.
Pakistani authorities arrested seven suspects, including LeT operations commander Zakiur Rehman Lakhvi, on charges of planning and financing the attacks but their trial has been marred by repeated delays and controversies.