A man has been arrested for his own protection after dousing himself with petrol and threatening to set himself alight at the Cairns Airport.

The domestic airport was evacuated about 5:15pm.

Former presenter of Media Watch, Jonathan Holmes, was at the airport and said witnesses told him the man doused himself with petrol but did not use the lighter in his hand.

"My wife had gone in before me, and one woman had told her that she had seen someone pouring petrol all over themselves and was about to set themselves alight," he said.

"However it appears that that did not actually happen.

"There was a strong smell of petrol."

Holmes said the man was taken away by an ambulance.

The Australian Federal Police said he was in custody for his own protection.

"The airport terminal has been evacuated due to the need to clean up flammable liquid that has been spilt," a spokesperson said.

Cairns Airport said the incident is under control.