Prince Harry and a "puffing and panting" Scott Morrison will climb the Sydney Harbour Bridge to officially welcome Invictus Games athletes.
The Duke and Duchess of Sussex say they want to meet as many Australians as possible when they tour the country this month.
Prince Harry and the Duchess Meghan will visit Sydney, Melbourne, Dubbo in NSW and Queensland's Fraser Island on their October 16-28 tour.
To officially welcome the Invictus Games to the city, Prince Harry, the prime minister and athletes will scale the bridge to plant the Invictus flag.
"I suspect he's going to get up there a little quicker than I will and as well as the other athletes who'll be going up there," Mr Morrison told reporters on Friday.
"They'll have a bit of a giggle at me puffing and panting all the way up to the top. My brother is a paramedic, so I might have to take him in tow."
The Invictus Games are an Olympic-style event for disabled and ill service people.
"This year's games will emphasise the integral role played by servicemen and women and their families and friends," Harry and Meghan's private secretary Sam Cohen said.
The newlyweds, who are on their first major tour since their wedding in May, want to meet as many locals as they can in Australia and then Fiji, Tonga and New Zealand, he said.
They will fly to Dubbo for the day where they will visit the Royal Flying Doctor Service and learn about the drought from a farming family at their property before attending a community BBQ.
In Melbourne they will take a short ride on a local tram to South Melbourne, where they will take part in a beach clean up with school students.
The Duke and Duchess will fly to Fraser Island for the day, where they will learn about conservation from traditional elders and rangers.
In Sydney they will visit the koala enclosure and meet conservationists at Taronga Zoo, meet with a youth mental health group at Bondi Beach and see a rehearsal of the Bangarra Dance Company.
"It's a great thrill having the royals come out. They're so great. Wherever they go, they just fill people with hope," Mr Morrison said.
