UN could not take any action on the statements made by Bhutto's husband Asif Ali Zardari, she said.
Zardari had demanded a UN investigation along the lines of the probe into the killing of Lebanese Prime Minister Rafiq Hariri.
"In case of Hariri's murder, the request was received from the Lebanese government," Montas told a press briefing.
Asked whether the request would have to come from President Pervez Musharraf himself, she said the executive branch of the government has to seek the inquiry. She, however, declined to answer whether the Secretary General himself could take action on the request or it needs to be referred to the Security Council. "That would depend on the nature of the request," she said.
Asked why Musharraf would ask for an independent inquiry as fingers have been pointed towards his government, she refused to give a direct reply saying the request for UN's involvement has to come from the Pakistani government.
(Reporting by Dharam Shourie)