He has installed the 2m-high work, Sustainable Triptych, to protest the Southland District Council's plan to erect a 75m sea wall nearby.
The council says the sea wall will prevent coastal erosion damaging Mullet Rd, the only access into the tiny settlement west of Riverton. But Brown and his partner, Susan McLaughlin, who have lived at Cosy Nook for 15 years, oppose the council's plan because they believe the sea wall will worsen erosion in other parts of the coast, endangering the adjacent Cosy Nook Beach.
They are calling on the council to get expert advice on the coastal impacts and put in place a long-term solution to protect the coast.
''Erosion next to Mullet Rd isn't new. The council has had years to deal with it. Now, because they've neglected the problem for so long, they have to enact something urgent to stop the road being washed away,'' Brown said.
The couple have appealed Environment Southland's decision to grant consent for the sea wall and will enter into mediation with the district council to try to resolve the issue.
Brown is one of New Zealand's most recognised artists, with his major works selling for $10,000 or more. Sustainable Triptych consists of three painted panels depicting local Pahia Hill, with the sea in the foreground and native birds and wildlife. Figures in the central panel are protecting local kereru and karoro, and Brown said the word ''sustainable'' across the scene epitomised his hope for the future of the area.