Conservationist Bindi Irwin has tied the knot in a ceremony at Australia Zoo on Wednesday afternoon ahead of the Federal Government's deadline on the number of wedding guests due to the coronavirus pandemic, which came into place at midnight.

The 21-year-old daughter of the late 'Crocodile Hunter' Steve Irwin got engaged to her long-time American boyfriend Chandler Powell on her birthday last July.

Irwin posted on social media that she had got married to her "best friend" in a "small ceremony".

"There are no words to describe the amount of love and light in my heart right now."

She said the coronavirus outbreak and the Government's restrictions meant she had to "change everything" and that they did not have guests at the wedding.

"We wish all of our friends and family could have been there with us, however it's lovely that we will be able to share photos and videos," she said.

Her white gown was spotted poking out underneath a huddle of people under umbrellas next to a large white SUV at the venue.

Photographers and camera crews were in place, with a musician holding a guitar waiting at the end of the aisle.

Two easels displaying photographs had also been set up.

Dozens of people were spotted at the venue, including zoo staff cradling koalas.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 22 seconds 22 s A white gown could be seen poking out underneath a crowd of people huddled under umbrellas.

The pair met at Australia Zoo.

"Chandler, close to six years ago I fell in love with you and every day since has been a whirlwind of adventure and true happiness," Bindi wrote in a social media post when the couple got engaged.

"I'm so looking forward to spending our forever together as your wife.

"Here's to a lifetime of friendship, purpose and unconditional love — now let's get married already!"

The pair met at Australia Zoo. ( AAP: Darren England )

Chandler has previously said proposing to her "in her very favourite place in the zoo, surrounded by animals, seemed like the perfect way" to do it.

Overnight, Bindi posted a childhood photo on Instagram in tribute to her father, late wildlife warrior Steve Irwin, who died in 2006 from a stingray barb wound.

"Thank you for being my guiding light. You're always with me," she wrote.

Chandler was a wakeboarder from Seffner, Florida. He now works at Australia Zoo.