IT ALREADY has an international airport, a petroleum refinery and a shipping terminal on its shores. Now Botany Bay could also become home to a huge marina and pier with a crystal-shaped building at its end.

Rockdale City Council is pushing ahead with a radical idea to transform the waterfront at Brighton-le-Sands into a 300-berth marina and pier dominated by a 50 metre-high structure known as The Crystal.

After consultation with the Department of Lands, which owns the site, and NSW Maritime, the council has called for expressions of interest from the private sector to determine whether the project is financially viable.

"We are looking for the private sector to build it, own it and operate it," the council's general manager, Chris Watson, said.

He said the cost of the project would be about $80 million.

Even with interest from the private sector, the development would ultimately require government backing.

Under the plan, The Crystal would contain a cinema, a restaurant and exhibition space.

The Rockdale Mayor, John Flowers, said: "The council is prepared to encourage innovative proposals that add value to the area and enhance the social and physical enjoyment of local and regional visitors."

A NSW Maritime spokeswoman said the regulatory authority was in favour of infrastructure that supported the boating community.

It would undertake a navigational assessment if the the council were to lodge an application, she said.