More than 800,000 people have fled a major military offensive against the Taliban in a Pakistani tribal area, officials say.

Tens of thousands of families have left the North Waziristan tribal area for the nearby town of Bannu.

Hundreds more have moved further afield to the towns of Lakki Marwat, Karak and Dera Ismail Khan since the attacks began in mid-June.

Officials from the FATA Disaster Management Authority (FDMA) said on Wednesday they were checking registrations for duplicates, meaning the figure might go down.

The military is using troops, tanks and jets in North Waziristan and has vowed to wipe out strongholds that insurgents have used to mount countless deadly attacks in recent years.

Civilians flee Pakistan’s Waziristan region. Photo: AAP

“Some 833,274 people or 66,726 migrating families from North Waziristan were registered in cities of Bannu and Peshawar until Tuesday evening,” Arshad Khan, FDMA director general, told AFP.

Khan said 361,459 of the displaced were children and 248,633 women.

The military said on Tuesday jets bombed and destroyed seven insurgent hideouts in Degan village, a stronghold of Taliban militants, killing at least 13 rebels.

So far 399 militants and 20 soldiers have been killed in the offensive, according to the military.

The area is off limits to journalists, making it impossible to verify military claims about the number and identity of those killed.

The assault was launched on June 15 after a dramatic attack on Karachi airport in June, which killed dozens of people and marked the end of a faltering peace process with the Pakistani Taliban.

The rugged, mountainous area has been a hideout for years for Islamist militants of all stripes, including al-Qaeda, the home-grown Tehreek-e-Taliban Pakistan and foreign fighters such as Uzbeks and Uighurs.