Conservationists honour late reef activist as 'tireless fighter'

The late Felicity Wishart is being hailed as one of Australia's most dedicated conservationists, who worked tirelessly to protect the Great Barrier Reef.

But she was also simply "Flic" - a beloved colleague, mentor and friend.

The respected environmentalist died suddenly in her sleep on Sunday night.

She was 49 years old and leaves behind a partner and two young sons.

Until her untimely death, she had served as the dedicated Great Barrier Reef campaign manager for the Australian Marine Conservation Society.

"None worked harder, with as much grace and achieved as many results to protect our heritage," an AMCS statement read.

"She combined great warmth and humility with an ability to understand and fearlessly challenge powerful forces that threatened our heritage."

Previously, Ms Wishart had worked for the Queensland Conservation Council and The Wilderness Society.

The late conservationist was a creative campaigner and had been instrumental in the push to phase out broadscale land clearing in the mid-2000s, the QCC said.

With more than 20 years experience in environmental advocacy, she also served as a mentor to up-and-coming female conservationists.

She was a "wonderful Australian" and her passing was terrible news, former Australian Greens leader Bob Brown said.

Her work on marine reserves also helped secure 25 state-based lots in NSW, South Australia, Western Australia and the Northern Territory, comprising more than three million hectares.

Most recently, she had scrutinised Queensland's Abbot Point project by rallying against "reckless industrialisation".

It was this energy and resilience in communicating her message that made `Flic' such a valuable campaigner, AMCS said.

"All Australians, whether they realise it or not, owe a debt of gratitude for her work," AMCS said.

"Her fight is our fight."