A suicide bomber has apparently detonated his explosives-laden vehicle prematurely in a former stronghold of the Pakistani Taliban, killing a married couple in a nearby car.

A local administration official, Rehmant Ullah, said on Monday that the bombing happened in North Waziristan, a district in the Khyber Pakhtunkhwa province of northwest Pakistan, bordering Afghanistan.

He said a team from the bomb disposal unit was also present nearby when the blast took place but they escaped unharmed.

"We suspect that the suicide bomber detonated his explosives either by mistake or prematurely, but it killed a man and his wife whose car was near the vehicle of the bomber at the time of the blast," he said.

It is unclear who dispatched the car bomber to the area, but suspicion is likely to fall on the outlawed Pakistani Taliban, who are known as Tehrik-i-Taliban Pakistan, or TTP, and who have stepped up attacks on security forces since last year.

Although the Pakistani military claims it has cleared the North Waziristan region and other former tribal areas in the northwest of militants, the violence has continued, raising concerns that terrorists are regrouping in the area.