In her fourth Boyer lecture, an extract of which is published in today's Herald, Professor Langton attacked Professor Flannery for comments in a Quarterly Essay article she said suggested he believed land was not ''safe'' if it was owned by Aboriginal people.

''Even under Labor governments with a strong green bent, national parks are not always safe,'' Professor Flannery wrote in the essay. ''In 2010, the Queensland Bligh government began the process of degazetting a large part of Mungkan Kandju National Park on Cape York Peninsula with a view to giving the land back to its traditional Aboriginal owners.''

Professor Langton, the foundation chair of Australian Indigenous studies at the University of Melbourne, suggested Professor Flannery had succumbed to the ''environmental campaign ideology that Australia's first people are the enemies of nature''.

But Professor Flannery said he had been misunderstood. ''In writing that national parks are not 'safe', I meant they are not secure as a permanent part of the national parks estate. I expressed no view whether biodiversity would be more or less secure under indigenous management … biodiversity has done best where NGOs and indigenous groups have worked,'' he said.

Professor Langton said the ''racist assumption in the green movement about Aboriginal people being the enemies of the wilderness'' had been a recurring theme in deals between conservation groups and state governments to ''colonise Aboriginal land under the Green flag'', citing as an example the Wild Rivers Act to limit development on Cape York, which has been repealed by the Newman government.

Professor Langton's lecture will be broadcast on ABC Radio National on Sunday at 5.30pm.