"However, we felt this was an ideal opportunity for him to get used to some of our systems and familiarise himself with the playing group.
"Despite only arriving back from the Rugby World Cup last week, Henry was keen to travel which underlines the passion he has to be part of this squad."
Ed Jenkins skippers an experienced Australian squad which welcomes the return of star centre Cameron Clark after a minor hamstring problem.
Pat McCutcheon (hamstring) and Nick Malouf (knee) were not considered due to injury.
Three players will be omitted from the final squad on Thursday.
"We have a belief that we will perform and gain the desired result," said Walsh.
"However, with a spot at the Rio Olympics on the line in Auckland, we are under no illusion that now is the time to deliver.
"For us, it is all process and executing under pressure as there are seven other teams looking to fulfil their own Olympic dream."
Australia will play Nauru, Cook Islands and Tonga in Pool A matches on day one on Saturday. Pool B features Samoa, Papua New Guinea, American Samoa and the Solomon Islands.
"I've heard many people say Samoa will be our main opponents for that coveted spot but I don't buy into that at all," said Walsh. "As per usual, we will be paying due respect to our pool and won't be looking any further than day one.
Australian squad (three to be omitted): Cameron Clark, Tom Cusack, Allan Fa'alava'au, Con Foley, Pama Fou, Lewis Holland, Henry Hutchison, Greg Jeloudev, Ed Jenkins, Tom Lucas, Sam Myers, Jesse Parahi, Henry Speight, James Stannard, Michael Wells.
- AAP