South Australia's former Liberal leader says he is taking medical leave after the emergence of a video, which allegedly shows him snorting powder off a plate.

In the statement, David Speirs — who has previously strenuously denied any wrongdoing — said the past few days had been "exceptionally distressing" for him and his loved ones and that he had engaged "legal counsel to assist me to navigate this difficult matter".

"I have consulted with medical professionals in the last 24 hours and have been advised that I should take time away from work to concentrate on my health," he said.

"I intend to follow that advice and am now on medical leave, but will be regularly consulting medical professionals."

Previously, Mr Speirs reportedly told News Corp, who released the footage, that it was a "deepfake" or artificially generated video that was "very troubling".

In his statement today, Mr Speirs also said he was "deeply grateful for the overwhelming support that I have received from parliamentary colleagues, from Liberal Party members, and from my community."

Mr Speirs resigned as the South Australian Liberal leader on August 8.

His statement said he left the leadership of the party as he had "run out of energy and the feeling of burnout" had been "compounded in recent days".

"As a consequence, my emotional health and wellbeing has been significantly impacted, leaving me feeling exceptionally vulnerable and at risk," he said.

"I have always put South Australians first, but now I must take some time to focus on my own health and wellbeing as any other person should."

Mr Speirs also said he did not plan to make any further statement.