James Fox, of Invercargill, will be doing the same with merino fleece.
Mr Stuart won junior judging national competitions at the New Zealand Agricultural Show) in November last year.
Winners in the beef and dairy sections will also be competing in their respective competitions in Perth.
Mr Stuart (25) manages the 180ha Willowbank sheep and beef merino finishing property near Tarras for the Lucas family.
He runs 3500 to 4000 stock units and has a keen interest in the business's stud operation.
''My judging competition is on September 30,'' Mr Stuart said.
''I don't know what to expect.
He said he had not done much training for the competition as he worked with sheep every day.
''I am always judging them, looking at them.''
However, he has received advice, help and practice from Armidale Merino Stud owners Simon and Allan Paterson, near Gimmerburn.
Part of his prize was a trip to the Canberra Royal Show in March, where he was an associate judge.
He is looking forward to the Perth trip.
He is enthusiastic about stock judging, and would like to gain further experience at more shows.
''For me, it was a good way to get out and learn, and it looks good on the CV.
''I want to promote junior judging to any young person keen to learn.''
Mr Fox won the 2018 New Zealand Merino Fleece Young Judge of the Year competition in Hawke's Bay last year.
From a sheep and beef background in North Canterbury, Mr Fox studied accounting at the University of Otago and moved down to Invercargill for work.
Now, at 23, he works for Findex, formerly Crowe Howath, Invercargill.
He also is a member of the Grand Toastmasters Club, Invercargill, plays social netball for ''The Stragglers'' as well as rugby for Marist.
He also belongs to the Thornbury Young Farmers Club and is also treasurer for the Otago/Southland regional committee.
