The 17-year-old pop star was attacked with six eggs from two directions during his performance at the city's Acer Arena on Friday.
Bieber fans were outraged after first two, then a further four eggs smashed within a metre of the Canadian superstar.
But according to onlookers Bieber barely missed a beat and a helper had soon cleaned up the mess.
The response from Justin's True Beliebers was swift as they took to the internet to condemn the unprovoked incident.
One fan wrote on Twitter: 'Dear person who threw eggs at @justinbieber in Sydney, you now have over #9millionbeliebers after you, be afraid! We go harder than hard!'
Bieber has since jetted to Melbourne where he will be performing on Monday and Tuesday night in the next leg of his My World Tour.
Meanwhile, Fighter actor Mark Wahlberg has revealed that he is set to star with Bieber in a new movie.
Wahlberg was reportedly so impressed with the singer's basketball skills that he has asked him to appear alongside him in a film about the game.
The Hollywood star told MTV: "Justin Bieber and I are going to do a movie together. We're putting it together ... We talked to him about doing it and he loved the idea. He sent me a video of himself and yeah, I think he's really talented."
Bieber has been keen to get back in front of the cameras since his turn in US crime drama CSI. He said recently: "I definitely want to do more acting, and further my career in that area, that's something I would love to do."