The man, a trainer in his 30s, suffered two puncture wounds to his neck after being bitten by one of the big cats.
He was flown to the Royal Brisbane Hospital by the Care Flight helicopter.
Australia Zoo keeps three Bengal and eight Sumatran tigers.
Zoo director Wes Mennon said a group of co-workers nearby saw the attack and helped drag the trainer away from the tiger.
“At the time of the incident, our emergency response team were on the scene immediately.
“They acted professionally and calmly. My hat goes off to them,” he said in a statement.
The Department of Community Safety said the man was in a serious but stable condition this evening.
Mr Mennon said the trainer had nine years of experience with big cats and raised the tiger since it arrived at the zoo as a cub.
“Our priority is the wellbeing of the handler, who is a valued member of our Australia Zoo family,” he said.
“Our full support is with the handler and family.”
Australia Zoo offers visitors photos with the tigers at 3:15pm every day for $400 per person.
On the zoo’s website it has a list of rules for visitors who partake in the photo sessions.
“Please remember that Big Cats are predatory animals and are quite capable of exercising their natural instincts,” rule number 12 says.