The US does not confirm drone attacks, but its forces in neighbouring Afghanistan and the Central Intelligence Agency are the only ones known to use the unmanned aircraft capable of firing missiles.
Reporters familiar with Mehsud said the voice appeared to be his, but it was impossible to confirm if it was recorded before or after Thursday's raid.
Mehsud is know to have recorded a number of similar tapes after an attempt on his life in October.
Conflicting reports emerged from intelligence agents and security officials on Friday, with some saying Mehsud was injured, while others said the he and some of his senior commanders were probably killed.
"So far we do not have confirmation of him either getting killed or getting injured. It will take a little more time to confirm this or otherwise," Major-General Athar Abbas, a military spokesman, told the AFP news agency.
The Taliban has issued a number of statements denying Mehsud's death, and Azam Tariq, one of their spokesmen, said his boss had left the Shaktoi area struck by the missiles "40 to 60 minutes" before the raid.
"Hakimullah is alive and safe. I met with him last night, there was not even a scratch on him," Tariq told AFP on Friday.
Mehsud took over as leader of the Pakistani Taliban five months ago, after Baitullah Mehsud, his predecessor, was killed in a drone attack.
The Taliban denied Baitullah Mehsud's death for weeks, apparently amid fierce infighting over his successor.
The "Mehsud audiotape" was released against a backdrop of continued violence in different parts of Pakistan.
A suicide bomber attacked a military vehicle in the southern part of Pakistani-administered Kashmir on Saturday, killing two soldiers, security officials said.
The bomber attacked the vehicle as it was travelling near the town of Rawalakot, the officials said.
Chaudhry Raqeeb, a senior administrative official, said two security personnel were injured and "immediately shifted to the nearby hospital".
On December 27, a suicide bomber killed seven people outside a Shia Muslim mosque in Muzaffarabad, the capital of Pakistani Kashmir.
'Wanted man' killed
Friday's drone attack in North Waziristan that allegedly targeted Mehsud, left up to five anti-US fighters dead, Pakistan intelligence officials said.
One of those killed was on the FBI's most-wanted list, they said.
Jamal Saeed Abdul Rahim was reportedly wanted for his alleged role in a deadly 1986
plane hijacking and had a $5 million bounty on his head.
The FBI's website identifies him as a Palestinian with possible Lebanese citizenship, who was a member of the armed Palestinian group Abu Nidal.
The Pakistani officials called him an al-Qaeda member.