At least 18 people were killed and 22 injured on Saturday when dozens of homes in northern Cairo collapsed after being hit by a massive rockslide, Egyptian emergency services said.

Several huge boulders weighing "hundreds of tonnes" broke off Moqattam hill overlooking the capital's Deweka district, one security official said on condition of anonymity.

"The rockslide occurred at 8:50 am (0650 GMT), and the provisional toll stands at 18 dead and 22 injured," the official said. "The rocks hit dozens of homes, causing them to collapse."

The cause of the rockfall was not immediately known.

Local deputy Haidar Bardadi told Egyptian television the toll could rise drastically, saying 35 homes had been crushed and between 150 and 200 people were trapped beneath the rubble.

Labourer Sarghalo Gharib, 24, told how he had lost eight members of his family in the landslide -- five sisters, a sister-in-law and her two children.

"It was horrible, like an earthquake. There had already been collapses, and the government did nothing to evacuate the district," he said angrily.

Police cordoned off the area and specialist dog handlers were deployed in the debris to try and locate survivors.

Rescue teams on site were struggling to make progress because of the size of the boulders. They were being forced to wait for the arrival of cranes and heavy lifting equipment to allow them to move the rocks.

Frustrated emergency workers stood by as they awaited the arrival of the specialist machinery needed to move the massive boulders.

An AFP journalist at the scene of the accident described scenes of panic as the residents of the poor and densely-populated shantytown neighbourhood struggled to search for missing friends and relatives.

"Two years ago the authorities warned us that it would fall on top of us, and today the drama has arrived," said Jamal Badr, 32, whose brick-built home was buried in the rockfall.

One local resident, who requested anonymity, told AFP that the majority of the properties destroyed in the landslide were inhabited and that they were mainly two-storey buildings.

Cairo Governor Abdelazim Wazir arrived at the disaster scene to monitor the rescue operation amid fears that the death toll was likely to rise.

Most of the brick-built dwellings in Deweka district have no more than two floors and are described as "unofficial." They were put up without adhering to planning regulations and without construction permits.

The arid Moqattam hill is broken up by chalky rock slopes, and a number of unofficial housing areas are at its base, along the length of the main road into the city.

Members of the Zabbalin Copt community live there, working mainly in collecting and sorting the rubbish created in a sprawling capital city that is home to about 20 million people.

Egypt has a poor track record of building safety often blamed on the flouting of construction regulations, particularly involving adding extra floors without permission.

In July five people were killed, including seven-year-old twins, when a three-storey building in Egypt's Nile delta collapsed.

Last December 35 people were killed when a 12-storey building in Alexandria came down. Two years earlier, in the same city, the collapse of a six-storey building killed 19 people. Three extra storeys had been added illegally.

Tougher legislation against construction companies ignoring the law was introduced in 1996 after a building in Cairo's Heliopolis residential area caved in, killing 64 people.