The cliff fall happened at Seaford Head yesterday evening.
A Maritime and Coastguard Agency spokeswoman said: "At 5.30pm yesterday, March 15, HM Coastguard received a report of a landslide in the Seaford Head area.
"The Environment Agency, the British Geological Survey and West Sussex County Council have been informed."
There was a large cliff fall at Seaford Head on March 15 Credit: Eddie Mitchell
Images taken today show the aftermath of the landslide, with an enormous mound of white rock piled up at the foot of the cliffs.
The rock covers part of the beach and extends into the sea.
Rainy weather last month caused cliff tops to become crumbly and unstable, with coastguard crews responding to a series of dangerous incidents as a result.