The Berejiklian government has rejected claims it gagged scientists due to address an Australian Academy of Science conference on the damage caused by feral horses in the Kosciuszko National Park, including wrongly claiming a key researcher was away in China.

Organisers of the Kosciuszko Science Conference say they only learned a day prior to the November 8 gathering that David Eldridge, a senior principal researcher with the NSW Office of Environment and Heritage, was overseas and unable to co-present a global analysis of feral horses.

Professor David Eldridge, a senior research scientist with the NSW government and UNSW, was denied the chance to speak at the Kosciuszko Science Conference.

It is understood Dr Eldridge, who is also a professor at the University of NSW, had been in discussions for weeks with senior OEH staff about removing words from his abstract, such as "invasive" because they deemed it "emotive", and to prefer "wild" over "feral". Professor Eldridge was also not to answer questions after his talk.

However, OEH eventually told the ecologist he couldn't attend. A staff member then rang the academy to say he was still in China - a country he had recently visited.