Watch: Sarah Walker bikes around edge of Sky Tower

BMX champion Sarah Walker has completed a new bike track 192 metres in the air.

The 2012 Olympic silver medallist rode precariously around the one-metre wide edge of New Zealand's tallest building to celebrate the SkyWalk's 10th birthday.

But she didn't just do it once - she rode the circuit five times in excitement, even adding in a wheelie for good measure.

Walker and her bike were tethered to an overhead trolley system for safety, but it was still a nail-biting ride for the athlete.

"Getting out onto the ring it felt as if I was about to start a world championship race," she said. 

"Every time around was scary, I think it almost got more scary as my brain realised what I was actually doing." 

The stunt was a world-first, and is considered the most dangerous act ever performed on the SkyWalk. To top off an adrenaline-fuelled afternoon, she finished her visit with a bungy jump back down to solid ground.

Walker said she doesn't think she'll be incorporating the sky-high track into her training schedule.

While she missed out on competing in the 2016 Rio Olympics due to a broken arm, the sportswoman has every intention of making it to Tokyo in 2020.