Rapid Bay's new $4million jetty won’t be completed before Christmas.

However, construction is well underway with pylon works and two-thirds of the jetty decking completed.

Unusually windy weather and rough seas in October caused delays, preventing the progress of protective coating and pylon works.

But with this milestone now completed, project manager Ben Hogarth said locals could expect the jetty to be finished early next year, depending on the weather.

Sea spray and rain could make welding difficult, so calm seas are essential when placing the concrete sleepers that form the deck into place.

Anthony King, a member of the Scuba Divers Federation of SA (SDFSA) and the Friends of the Rapid Bay Jetty, is disappointed the jetty would not be finished by Christmas but pleased with its progress.

"We would have loved to see is ready for Christmas, but we understand it's one of those things that is out of the Department for Transport, Energy and Infrastructure's (DTEI) hands.

"The nature of the project means it is dependent on the weather…but we are very pleased to see it going ahead."

The DTEI is reminding swimmers, fishers and divers that the area around both the old and new jetties is closed to ensure public safety during construction.

"Right now the Rapid Bay jetty is a construction site," acting project director Ian Llewellyn said.

"For their own safety, I urge marine enthusiasts to exercise caution and patience until the new facility is opened."

Rated as one of the country's top fishing and diving spots, access to most of the existing jetty was closed in December 2004 after it fell into disrepair from storm damage.

Plans to build a new $3.9 million structure were announced in September 2006, after the local community rallied for the future of the old jetty.

Mr Hogarth said hopes to complete the new jetty by January 21 were realistic, but will again be dependent on the weather.