The Gowan Brae estate in central Tasmania was bought by millionaire Utah lawyer Martin Polin at the height of the Cold War.

"He wanted to find the clearest place on earth where he could build a bunker within which his family and another family could survive a nuclear war and become the people of a new world," Tasmanian Aboriginal Land Council chairman Clyde Mansell said.

The 6750 hectares came onto the market after Mr Polin's death in 2007.

It comes with evidence of quarries used by Tasmania's Big River people to gather stone for their tools - and a bomb-proof bunker.

"It's an eyesore to see it. It's quite a unique structure," Mr Mansell said.

"The story goes that he, at one stage, had 12 trucks full of concrete up there ready to lay the bunker."

Aboriginal people from across Tasmania attended a signing ceremony yesterday after the land was bought for $3.3 million with federal government and Indigenous Land Corporation funds with the help of Tasmanian Land Conservancy.

The property, which borders a World Heritage Area, is now believed to be the largest piece of Aboriginal land on the Tasmanian mainland.

The bush food and medicine of the West Coast groups that passed through the area before European settlement will be among the cultural activities to return to the site, Mr Mansell said.

An Aboriginal name will also be discussed for the property.

"It's about taking people back to that landscape and getting them to understand it," Mr Mansell said.