The council had investigated the slip and its effect on the buildings at the top of the cliff and ensured the area below the slip was safe for the public.
Signs had been put up warning people to keep away from the area directly underneath the cliff.
Roberts said all occupants and owners in the affected properties were working with the Earthquake Commission.
He said unless further erosion directly affected buildings, the slip was a private matter and would be dealt with by owners and the commission.
The council was managing more than 90 similar cliff slips on public land across the region.
Realtor Ben Dellabarca and his flatmate were walking beneath the cliff on Sunday when rocks starting cascading down.
Dirt, rocks and even a retaining wall suddenly collapsed on to the beach below, narrowly missing the pair's dogs.