Rehman Malik, Pakistani's interior minister, said: "Information is pouring from that area that he is dead.
"We have some information, but we don't have material evidence."
Al Jazeera correspondent Kamal Hyder said: "The Pakistan goverment is planing to send a team in to that location to confirm the death or not.
"There are also reports there is an ashura [meeting] under way to pick a successor to Mehsud.
"There is not doubt there will be a swift succession, but Mehsud was a strong leader, so it will be difficult to fill that particular vacuum."
The missile raid reportedly destroyed the home of Akramud Din, Mehsud's father-in-law, on Tuesday morning.
Mehsud's second wife and his bodyguards were confirmed to have died in the air raid in Makeen, a difficult-to-access village in the tribal heartland near the border with Afghanistan.
Diplomats in Islamabad say Mehsud's death would mark a major coup for Pakistan, but many doubt it will help Western troops fighting the Taliban in Afghanistan as most of his focus has been on attacking Pakistan's government and security forces.
Mehmood Shah, a retired brigadier former chief of security in the tribal areas, said Mehsud's death would be "quite a setback" for the Taliban.
"He is the one man who really organised the Taliban, kept unity among them and really forwarded the agenda with a lot of ... strategic thinking," Shah said.
Karin von Hippel, a security expert at the Centre for Strategic and International Studies in Washington, said: "What happens ... is another comes in and takes their place pretty quickly."
Neither the Pakistani nor the US government have confirmed the attack. The US routinely denies operating within Pakistan territory.
The US and Pakistan say Mehsud is linked to al-Qaeda and has been involved in dozens of suicide attacks, beheadings and assassinations, including the killing of Benazir Bhutto, the former Pakistani prime minister.
The US has placed a $5m bounty on Mehsud's head and branded him "a key al-Qaeda facilitator" in Pakistan's tribal belt.
A relative of Mehsud's dead wife had initially said the Taliban leader was not present when the missile struck, but rumours that he had either been wounded or killed refused to die down.
Mehsud declared himself leader of the Pakistan Taliban, grouping around 13 factions in the northwest, in late 2007.
His estimated 10,000-20,000 fighters have been blamed for a wave of suicide attacks inside Pakistan and on Western forces across the border in Afghanistan.