Residents in a Pakistani town that was among the worst-affected by this week's massive earthquake are seeking help to rebuild their damaged homes.

Authorities said Monday's quake damaged 8,453 homes and 113 schools in Pakistan's impoverished north-west.

Rescuers in Afghanistan and Pakistan are struggling to reach regions stricken by the magnitude-7.5 quake, which was centred on Afghanistan's sparsely populated Badakhshan province that borders Pakistan, Tajikistan and China.

The quake left at least 258 people dead in Pakistan, 115 in Afghanistan and three on the Indian side of the disputed region of Kashmir.

Casualty figures are likely to leap once relief workers return from remote villages that can be accessed only by foot or donkey.

The earthquake, with its epicentre close to district of Jarm, damaged many of the few existing roads, officials said.

Dropping aid by air will be the only way to reach many of the needy, but those operations are not likely to start for many days, until survey teams on foot return and report on the damage.

One of the worst-affected Pakistani towns is Shangla, where 70-year-old Zurqun Nain said his extended family was living at a relatives' home after the quake damaged his house.

"I had my own home before the earthquake. Now I am homeless at this old age," he said.

Another resident, Said Alam, said his family was still waiting for government help.

Monday's quake shook buildings in the capital, Islamabad, and cities elsewhere in Pakistan and Afghanistan for up to 45 seconds in the early afternoon, creating cracks in walls and causing blackouts.

The earthquake destroyed more than 7,600 homes across Afghanistan and injured 558 people, according to President Ashraf Ghani after he met disaster management officials.

He ordered the military to make assets available for the relief effort.

Badakhshan governor Shah Waliullah Adeeb said more than 1,500 houses there were either destroyed or partially destroyed.

The province's casualty figures of 11 dead and 25 injured "will rise by the end of the day, once the survey teams get to the remote areas and villages," he said.

Food and other essentials were ready to go, he said, but "getting there is not easy".

Many people in stricken areas were sleeping outdoors, braving freezing temperatures for fear of aftershocks.

Afghan authorities said they were scrambling to access the hardest-hit areas near the epicentre, located 45 miles south of Fayzabad, the capital of Badakhshan province.

Badakhshan is one of the poorest areas of Afghanistan and frequently hit by floods, snowstorms and mudslides.

Its valleys and mountains make access to many areas by road almost impossible at the best of times. It often has big earthquakes, but casualty figures are usually low because it is so sparsely populated, with fewer than 1 million people.

The Taliban issued a statement calling on all Afghans "not to hold back in providing shelter, food and medical supplies" to earthquake victims and said its fighters would also lend a hand.

The insurgents, fighting to overthrow the Kabul government for 14 years, have built a presence in northern provinces this year, notably in Badakhshan. Some districts, including Jarm, have been seized briefly by Taliban gunmen.

Officials have said it is part of their strategy to take control of strategically insignificant areas to force the Afghan government to spread its military resources ever-thinner in the fight to defeat the insurgency.