Musharraf was asked during an interview with the private Aaj television channel about the aspiration of Bhutto and Sharif to return from exile to lead their parties in parliamentary elections, due at the end of the year.
"No, they will not be returning before elections," Musharraf said in an excerpt shown before the screening of the full interview late Friday.
The announcement seems likely to deepen Pakistan's political crisis, in which the military leader faces accusations of authoritarianism as well as a growing challenge from Islamic extremists.
Musharraf has said he will ask lawmakers in the outgoing parliament to elect him to another five-year term as president. He has also resisted calls to give up his post as army chief.
Opposition parties were expected to challenge that stance before the Supreme Court, and have cried foul over Musharraf's decision in March to suspend the court's top judge for alleged misconduct.
There had been speculation that Musharraf would team up with Bhutto under an arrangement that would see her return to the country, in return for her Pakistan Peoples Party's support for his presidency.
But deadly violence between government and opposition supporters in Karachi last weekend, and now Musharraf's unequivocal rejection of Bhutto's return, appear to have killed off the chance of a pact with her party, which espouses a similarly moderate, pro-Western course.
Musharraf banished Sharif to Saudi Arabia for 10 years after seizing power in a bloodless coup in 1999. Bhutto left the country months earlier to avoid arrest in corruption cases registered against her by Sharif's government.
Musharraf has dismissed both of them as corrupt and incompetent, but had recently appeared more conciliatory, and officials recently scaled back corruption investigations against her.
In the television interview, Musharraf, a key ally of the United States in its "war on terror," said extremism and militancy was increasing in Pakistan.
"There is a rise of extremism and militancy in the country. We have to counter it. We have to face it," he said.
He said al Qaeda was still present in the area of Mir Ali, a town in the North Waziristan region near the border with Afghanistan. The remote area is considered a potential hiding place for Osama bin Laden and his deputy Ayman al-Zawahri.
The government in 2006 signed a peace deal with pro-Taliban militants in North Waziristan, pardoning them in return for a pledge that they would halt attacks on security forces and raids into neighboring Afghanistan.