Part of Clacton Pier has collapsed into the sea while workers were carrying out refurbishment work.
It happened as new concrete decking was being laid in an area closed off to the public.
The Pier director Billy Ball said that as this was taking place, excess vertical movement of the piles caused four bays of the existing slab to fail.
Mr Ball added that similar tried and tested methods had been used in other areas of the Pier over the past ten years. So far around 4,000 square metres of such work has been carried out and this area involves 140 square metres.
Structural engineers are currently assessing the situation.
The affected section of the pier had been set aside for the new Looping Star ride due to be opened in the Spring.