Drone footage has revealed the extent of damage to waterfront properties at Collaroy, where the beach has been washed away and buildings are teetering on the brink of collapse.

The northern Sydney suburb copped a battering on Sunday night as waves up to eight metres high lashed the shoreline.

People were evacuated from about seven homes and a unit block as backyards were washed into the ocean.

A huge low pressure system combined with a king tide to bring widespread coastal destruction over the weekend.