Iron Boy, aka Domenic Pace, has defeated Ultron in a vicious battle on Sydney’s Opera House steps after the superhero earlier rescued a reporter from his evil clutches.

The nine-year-old had earlier made a trip by police speed boat to Clark Island to save Make-A-Wish Foundation reporter Hope Joy after she was kidnapped by Ultron’s evil henchmen.

In a tough battle witnessed by hundreds of cheering bystanders, Iron Boy not only defeated his arch-nemesis Ultron, but also a group of henchmen, on the Opera House steps.

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The superhero was then congratulated by NSW police chief Andrew Scipione who called him “Sydney’s true hero” before being presented with a medal.

“It was also my great honour to present Domenic, or should I say Iron Boy, with a special acknowledgment, a Commissioner’s Award for Gallantry,” Commissioner Scipione said.

“Not only has Domenic battled villains and saved his city, he’s stared down his illness and won the day.”

Domenic, who has cystic fibrosis, was granted his dream to be Iron Boy for a day by the Make-A-Wish Foundation.

He said his ideal super power would be to heal people.

The south-west Sydney schoolboy started his day in a park where he was recruited via helicopter to go on a secret mission in a joint project between the foundation and NSW Police.

Iron Boy defeats two of Ultron’s agents at the Opera House. Photo: ABC

On Thursday morning Commissioner Scipione himself called on the nine-year-old to help rescue Ms Joy and stop Ultron.

“Iron Boy we need your help. Make-A-Wish reporter Hope Joy has been kidnapped,” Commissioner Scipione said in a video addressed to Domenic.

“Officers have confirmed that Clark Island has been taken over by Ultron’s henchmen and that Hope Joy has been held captive.

“If I have one wish it is for you to help us Iron Boy.”

Domenic watched the message from NSW Police Headquarters then nodded as he was asked by Assistant Commissioner Mal Lanyon if he was prepared to save the day as Iron Boy.

It did not take long for Iron Boy to spring into action, first travelling to police headquarters in Parramatta by a police helicopter to be briefed on his special mission and to put on his armoured suit.

He then travelled to Clark Island by police speed boat from the Parramatta Warf to start his mission.

Domenic Pace on the way to complete his mission. Photo: NSW Police Force 

The young superhero grinned broadly as he was handed the high-tech crime fighting ensemble.

He told the police and media he was “ready to get down to business”.

In an interview on 2GB, he confirmed that the chopper ride had been “awesome”.

“We saw a couple of fields, the Three Sisters … and Warragamba Dam,” he said.

“And we went through a bunch of cloud.”

When asked if he was going to save Sydney, the nine-year-old replied, “Yep”.

Assistant Commissioner Lanyon said the force was thrilled to be a part of the plan hatched by Make-A-Wish.

“It’s a great opportunity to do something for a little boy and obviously give back to the community,” Assistant Commissioner Lanyon told 2GB.

Iron Boy is awarded a medal of valour by NSW Police Commissioner Andrew Scipione. Photo: ABC

His mother said Domenic had always had a fascination with Iron Man.

“From a young age he would only answer to Tony [Tony Stark is Iron Man],” she said.

“He was a very caring child, more interested in helping children and other people than playing toys.

“He always wanted to know what was going on around him in the world and how he could help others.”

She said one day he stood up at the dinner table and said “I am Iron Boy” and the family “pretty much had to go with it from then”.

Hollywood’s Robert Downey Jr, whose alter ego is Tony Stark/Iron Man, has tweeted his support saying he’s sent a “very special boy on a top secret mission today”.

“Go get ’em Domenic!” he said.

#IronBoyAU If he had one super power it would be to heal pic.twitter.com/pemjY6QluV

— Lucy Marks (@LucyMarks) February 11, 2016

@nswpolice said they couldn’t have taken down mega-villain #Ultron without the help of #IronBoyAU @abcnews pic.twitter.com/7QBLL6Vt4Q — Lucy Marks (@LucyMarks) February 11, 2016

A hero to all, young and old. #IronBoyAU @abcnews pic.twitter.com/bZFZt73Eve

— Lucy Marks (@LucyMarks) February 11, 2016