BINDI Irwin has paid tribute to her late dad, Crocodile Hunter Steve Irwin, on what would have been his 55th birthday.

The 18-year-old shared a photo on Instagram of the Australian wildlife expert smiling at a cockatoo.

Always in our hearts.

A post shared by Bindi Irwin (@bindisueirwin) on

"Always in our hearts," she captioned the sweet shot.

Steve Irwin was filming the documentary series Ocean's Deadliest in 2006 when he was fatally attacked by a stingray.

His children, Bindi and son Robert, have followed in his footsteps, feeding crocodiles at their family's 100-acre Australia Zoo and appearing on various TV programs.

Last week, 13-year-old Robert appeared on the Jimmy Fallon show to promote a charity dinner in honour of his father.

Professing his love for wildlife, the teen said that dealing with animals was "in his blood."

"I actually grew up at Australia Zoo. I think I'm the luckiest kid in the world," he said.