First Nations artist Megan Cope used about 85,000 oyster shells from the Narooma Oyster Festival on the NSW south coast to create three large-scale public works in the Opera House precinct on Bennelong Point.

There is a decorative windbreak under the exterior staircase, a contemporary midden in front of Bennelong restaurant and oyster shells clinging to 200 timber poles on the northern boardwalk.

Cath Peachey, chair of Narooma Rocks, the organisation behind the oyster festival, said Ms Cope's work tended to explore the relationship between environment, geography and culture.

The work at the Opera House is about the recent and ancient history of Bennelong Point.

"Through the art installation Megan is raising the profile of the rock oyster which is what we are about and also its significance as a food source for her people," Ms Peachey said.

While in Ireland to accompany Gerard 'Doody' Dennis to the World Oyster Opening Championships in Galway and to pitch Narooma as host of the Oyster World Cup, Ms Peachey discovered how rare rock oysters were, accounting for just one per cent of global production.

While most of the world's oysters grow in nine to 12 months, rock oysters take five years to reach our tables.

"Over that time they are handled with care by farmers so what Megan is doing is adding to our collective care by caring for them in their next life," she said.

Rock oysters were also unique in that all the oysters Ms Peachey sampled overseas were grown in the sea, making them salty.

"Ours are so complex because we are growing them in estuaries as well," she said.

Oysters are improving the planet's water quality

"Even in New York they have oyster reefs to improve the marine habitat," Ms Peachey said.

She said oyster shells could be composted and farmers crushed them and used them on driveways.

"The installation will educate people about the rare and special thing we have," she said.

IN OTHER NEWS:

Over the course of the Narooma Oyster Festival, 20 Zero Hero volunteers monitored bins and directed people to put their oyster shells in specially designated bins.

Eurobodalla Shire Council sustainability education officer Alex King said small things triggered really big questions for people.

"They see something transformed into something beautiful.

"The big impact of that is the ongoing thoughts and behaviour changes," Ms King said.