Former Greens leader Bob Brown said Leslie (Les) Southwell, a Melbourne engineer, was a remarkable wilderness walker who first came to Tasmania in the early 1960s.

Mr Southwell, 88, was found dead outside his tent on Sunday morning after becoming separated from a friend three days earlier.

Police said he had been well prepared and equipped, with nothing to indicate the hiker had done anything untoward or wrong.

Mr Brown said Mr Southwell’s 1983 book The Mountains of Paradise: the Wilderness of South-west Tasmania was a classic of Australian wilderness photography.

“His depictions of Lake Pedder National Park are now national treasures,” he said.

A campaigner against the damming of the Franklin and Gordon rivers, Mr Southwell was “until the end ... a crusty advocate for restoring Lake Pedder”.

Victorian environmentalist Karen Alexander said Mr Southwell was dedicated to conservation, such as through the Lake Pedder campaign, Fraser Island and the Franklin.

“He saw the value of photography to convey the good message about wild places, like Peter Dombrovskis and Olegas Truchanas who also died in the wild,” she said.

“Les kept the campaign for Tasmania's south-west wilderness alive in Melbourne after the loss of Lake Pedder, paving the way for saving the Franklin.

“As a civil engineer, Les had argued strongly for alternative solutions to the flooding of Lake Pedder.”

Mr Brown said 50 years ago Mr Southwell observed for Tasmanian politicians “the idea of the wilderness experience seemed incomprehensible and they often seemed hostile to the very notion”.

“Nowadays wilderness is arguably Tasmania’s greatest tourism drawcard, thanks to advocates like Les Southwell,” he said.