The theft occurred within the first two weeks of April at the Mount Alfred Lookout, where a steel eagle created by Agency of Sculpture's Benjamin Gilbert for the Great River Road project was installed.

The steel hat is described as being slightly bigger than a normal hat and was hand-sculpted by a blacksmith.

Vandals also unscrewed a picnic table set.

Towong mayor David Wortmann said the theft was disappointing given the great feedback the artworks have received from locals and visitors.

"We were thrilled to secure this funding to highlight the Great River Road touring route so it is really disappointing to see some elements of the community taking advantage of the great work that's been done here," he said.

Agency of Sculpture won the tender for the artistic element of the project.

The $150,000 commission included a Murray Cod at Tintaldra, a Bogong Moth at Newmans Lookout, a rainbow trout at a new rest stop near the Khancoban township and a Murray Cray at Bringenbrong Reserve.

Anyone with information on the theft should contact the Tallangatta Police Station on (02) 6071 2204.