Hundreds gathered at the landmark to greet Harry, who has come to the end of a month-long attachment with the Australian Defence Force (ADF).
He spent more than half an hour meeting schoolchildren and shaking hands with fans, some holding signs which read ‘Marry me Harry’, ‘His Royal Hotness’ and ‘Gingers Rule’.
Victoria McRae, 21, wore a sequinned Australian flag dress and a plastic gold crown as she proposed to the Prince before surprising him with a kiss, according to the Australian Associated Press (AAP).
Harry, dressed in his military uniform, told her he would “have to think about that”, and then bit his knuckles.
“I got to kiss him. And I got to kiss the premier, who I didn’t know was the premier,” the student said. “I got Harry’s lips, I only got the premier on the cheek.”
She added it was not the first time she had popped the question to 30-year-old Harry, as on one occasion in 2013 she kayaked on to Sydney harbour with a sign.
Meanwhile, alongside a video of the prince meeting the public, Kensington Palace tweeted: “Prince Harry thanks the Australian public for the warm welcome during his stay.”
Another fan, Anne Woods, gave him a stuffed koala for his new niece Princess Charlotte, but while he thanked her, he said he wanted to keep it for himself,
“It was just lovely, just lovely to give him a gift for all the charity work (the prince does),” Ms Woods told AAP.
Also among those lining up to meet Harry was Graham Smyth, who took part in the Queen’s visit to Australia in 1954 as a flag-waving six-year-old.
He said the opportunity to see the Prince in person was “too good to pass up”.
Before meeting the crowds gathered near the opera house, the Prince took part in a military exercise in Sydney Harbour.