The $900,000 artificial offshore reef will be constructed using 20 purpose-built concrete modules, each five metres high and weighing over 23 tonnes.

Minister for Primary Industries Katrina Hodgkinson joined Kiama MP Gareth Ward as the modules were loaded onto a barge at Port Kembla on Friday.

Both said the installation of the reef would make the Shoalhaven the state's latest recreational fishing hot spot.

The structure is more than double the volume of the first offshore artificial reef, which was dropped off the Sydney coast in 2011.

Ms Hodgkinson said the modules, designed to withstand one-in-100-year storm events, would be deployed in 30-metre-deep water about four kilometres offshore from Shoalhaven Heads.

"Each of the concrete modules is specially designed to be self-weighted with no requirement for additional anchoring," Ms Hodgkinson said.

Mr Ward said the new reef would be a major drawcard for recreational fishers and would boost tourism opportunities.

"This artificial reef will create a new, high-quality fish habitat for a range of fish species and other marine life to benefit anglers in the region," Mr Ward said.

"Bait fish will colonise the reef, which will then attract larger target species including snapper and kingfish, providing a great fishing location for boat fishers."