Steve Irwin has been remembered as a "superhero" by his loved ones on the 20th anniversary of his death.

The Crocodile Hunter tragically died at the age of 44 in 2006 after his heart was fatally pierced by a stingray barb to the chest as he was snorkelling in shallow waters in Queensland, Australia, and his family have honoured the conservationist and TV star on Friday's (04.09.26) anniversary of his untimely passing.

In a message posted on Instagram, Steve's wife Terri Irwin wrote: "After 20 years, grief still walks with me like my shadow. With the passing of time I have gained more perspective and understanding.

"We were together as a family, on our crocodile research expedition, for what was to be our final six weeks together. Ours was to be a long and sweet goodbye."

Terri - who has children Bindi, 28, and Robert, 22, with Steve - continued: "Steve spent time with Bindi and Robert building swings and climbing trees. We all slowed down. Time slowed down.

"I believe that all of us, every one of us, gets to say goodbye. We just may not know that we're saying it. Hold every moment dear with the ones you love. Until we meet again."

Robert - who triumphed on the TV show Dancing with the Stars last year - shared a picture of himself as a baby looking up to his father on Instagram to mark the anniversary.

His post was captioned: "Your legacy is forever."

Meanwhile, Bindi posted a video of Steve describing her birth as the "most incredible wildlife encounter" of his life.

In a caption accompanying the clip, she penned: "20 years ago, today, the world lost the most passionate and dedicated wildlife conservationist. Our family lost our superhero. My mum lost the love of her life; my brother and I lost the greatest dad.

"Grief never truly leaves us; we walk alongside it every day. Where there is enormous grief, there is even greater love. In the last 20 years, I have watched the world mourn my dad with our family. I always thought that my dad's legacy is wildlife conservation; it turns out, his legacy is love. For our planet and for each other."

Bindi, who has daughter Grace, five, with her husband Chandler Powell, added: "I have a 5-year-old daughter who watches his documentaries every morning. She feels utterly loved by her 'grandpa crocodile' without ever having met him.

"My dad left a lasting impact so poignant that it will ripple out for generations to come. I believe with my whole heart that his love will live on forever. In all of us. In every kindness we show to the Earth. And that is a life and legacy worth celebrating.

"Dad, I love you with my whole heart. Thank you for being our guardian angel. And most of all, thank you for watching over my daughter now, too. She loves you so much. We all do."