The public is being warned to take care beneath the old Rapid Bay Jetty after some of the remaining walkway partially collapsed.

Image: Caroline Horn

The Scuba Divers Federation of South Australia (SDFSA) first raised the alarm on Tuesday, telling its members to take care in the area.

One diver commented that she and others saw part of the jetty collapse into the water on Monday, just as they were finishing a dive.

The Department of Infrastructure and Transport sent workers to inspect the site yesterday and is warning all divers, boat operators, snorkelers and swimmers to take care until it undertakes work to fix the situation.

The new Rapid Bay jetty was opened in 2009 and is very popular with recreational fishers.

The old jetty was 688m long and was built in 1940 by BHP to remove material from the nearby limestone and dolomite mine. 

It was later sold to the state government and used by Adelaide Brighton Cement. It ceased to be used for commercial purposes in 1990 and was closed in 2004. 

Since then, it has fallen into further disrepair.

Image: Caroline Horn