Southgate urges England understudies to seize chance against Australia
Southgate is set to name an experimental line-up as he rests his established stars ahead of Tuesday's key Euro 2024 qualifier against Italy.
England could seal their place at next year's tournament when they face the Italians.
But first Southgate will take a look at some of his fringe players against the Socceroos.
"It's one of the great sporting rivalries and if Australia have any sniff that we're not taking the game seriously, then we will be in trouble," the England manager told reporters on Friday.
"Our mindset has got to be spot on. Equally, we've still got a bit of work to do to qualify for a European Championship.
"We have good players and we need to give people opportunities to show what they can do.
"Most importantly, we have got good players and we need to have them in positions on the field where they can do their best work and feel comfortable, positions they play with their clubs, so that the transfer is as smooth as possible."
Jarrod Bowen will be hoping for a chance as the West Ham winger returns to the England set-up for the first time since September 2022.
Chelsea defender Levi Colwill could make his debut, while uncapped Arsenal striker Eddie Nketiah and in-form Aston Villa frontman Ollie Watkins will hope to prove a worthy back-up to England captain Harry Kane.
Southgate would not confirm who will skipper England on Friday, but it appears unlikely that Bayern Munich striker Kane will be leading the line.
"I think one of the things we always want to do is to make playing for England enjoyable," Southgate said of his selection plans.
"It's to take the tension out of playing for England, we want the lads to express themselves.
"Equally, when you play for England there is a pressure and you know that you're not going to get 10 opportunities unless you play well. Every player that comes into the squad experiences that."
Harry Maguire could feature for England after he was booed by Scotland fans at Hampden Park on his last international appearance in September.
The troubled Manchester United defender, who has lost his place for his club amid widespread mocking from rival supporters, was contacted recently by former England captain David Beckham.
Beckham expressed support for Maguire and Southgate said: "I can see from Harry's comments how much it meant to him.
"David has played at United, he has played for England, so he knows the world Harry is living in and it will have meant the world to him to get that support.
"Harry is a very strong character, but nonetheless he is a human being and I am sure a call like that would have meant a huge amount to him."