Pakistan has rejected a proposal to let the UN question the disgraced nuclear expert, AQ Khan, who has been under virtual house arrest since 2004.
Dr Khan is still seen by some as hero, despite the nuclear scandal
On Tuesday ex-PM Benazir Bhutto said she would let the UN nuclear watchdog put questions to Dr Khan, if she returned to office, reports said.
Many in Pakistan see Dr Khan as a hero for developing its first nuclear bomb.
In 2004 he confessed to leaking nuclear secrets to Iran, North Korea and Libya, sparking huge international concern.
Pakistan's Foreign Ministry said on Wednesday that the authorities had fully investigated Dr Khan's activities and had passed on the results to the UN.
The government's response came after Ms Bhutto was reported to have said that she would - were she to return to office - give the International Atomic Energy Agency direct access to Dr Khan.
The president has said that the nuclear scandal was "embarrassing"
She was responding to questions after making a speech on Tuesday in Washington, the Dawn and Daily Times newspapers said.
Ms Bhutto's Pakistan People's Party (PPP) was quick to play down her reported comments as "not very different from what the current government says".
But correspondents say the remarks are likely to stir much debate in the run-up to forthcoming elections in Pakistan.
Foreign ministry spokeswoman Tasnim Aslam said: "In case there is new information, in case there is something else that needs to be looked into, we would conduct investigations and we will provide information to the International Atomic Energy Agency.
"That will remain Pakistan's position."
Ms Aslam said other countries had not done as much as Pakistan to prevent nuclear proliferation.
President Musharraf pardoned Dr Khan shortly after he made a televised confession claiming sole responsibility for more than a decade of nuclear smuggling.
The government maintains that neither it nor the Pakistani military was aware of his illegal activities.
In a separate development, the PPP has announced that it will field a candidate for the country's forthcoming presidential ballot if President Musharraf is prevented by the Supreme Court from taking part in the vote because he is also head of the army.
The court was hearing closing arguments in the case on Wednesday and a ruling is expected imminently.
Nominations for candidates taking part in the presidential vote must be filed by Thursday.