SHE may be 'sweet sixteen' today but Bindi Irwin's birthday celebrations will be bittersweet without her dad Steve. 

Bindi was only eight when Steve Irwin was tragically killed by a stingray in 2006, but she admitted to People Magazine that the sadness felt when she lost her father 'never went away.'

"I remember after we lost dad, so many adults came up to me and said, 'Honey, time heals all wounds,'" Bindi said.

"That is the biggest lie you will ever hear. It doesn't. That kind of sadness never goes away. It's like losing a piece of your heart that you never get back."

Talking to Today Show's Lisa Wilkinson, Bindi described her dad as her 'superhero.'

"The one thing that I always wish is that he was still here to be able to talk to," she said.

"I still sometimes think that he's going to walk through the door and he's been on a long trip filming a documentary and he'll come home and we'll laugh it off, but that's not going to happen."

Bindi has also slammed Justin Lyons, the cameraman who was filming Steve Irwin when he was killed, after he spoke publicly about the incident on Channel 10's Studio 10 in March.

"It's really hurtful," Bindi told Who magazine.

"For as long as I live, I'll never listen to it. It's wrong as a family for us to hear about it."