A senior NATO official said Osama bin Laden and his deputy Ayman al-Zawahiri are believed to be living in relative comfort in Pakistan houses and not hidden away in a cave.

The official told CNN the two top al-Qaeda figures are not living together, but hiding close to each other somewhere in northwest Pakistan.

Al-Qaeda leader Osama bin Laden, in this undated photo, is believed to be living in northwest Pakistan, according to a NATO official. (Associated Press)

"Nobody in al-Qaeda is living in a cave," he told CNN.

He would not say how the coalition has this information, but CNN said he has access to some of the most sensitive information in the NATO alliance.

The official said bin Laden and al-Zawahiri are believed to be living in an area of rugged terrain and inhabited by independent tribes. They are reportedly being protected by locals and some members of the Pakistani intelligence services.

Pakistan's Interior Minister Rehman Malik denied the two men are on Pakistani soil.

Richard Holbrooke, the special U.S. envoy to Pakistan and Afghanistan, said there was nothing new to what the official was saying.

"We hardly have a day that goes by where somebody doesn't say they know where Osama bin Laden is," said Holbrooke, who was in Rome for a conference on Afghanistan.