Swansea's under-21 back row star Jonathan Thomas, who was promoted to the tour squad after an injury to Bath's Gareth Delve, will win his first senior cap against the Wallabies - Llanelli back row Dafydd Jones misses the match through injury (sternum).
Thomas is one of six new faces in the team from the side that faced the Barbarians less than two weeks ago with wing Tom Shanklin, scrum-half Gareth Cooper, prop Gethin Jenkins, lock Robert Sidoli and centre Jamie Robinson all returning.
And two positional changes see Mark Taylor move to inside centre and Rhys Williams revert back to full-back where he has won the majority of his 27 caps.
For Cardiff's Robinson, Saturday will mark his first international match since facing the All Blacks in Cardiff last November having missed the entire Six Nations with an ankle injury.
'Dafydd Jones' unavailability has given Jonathan his chance and we are sure he will be able to repeat the impressive form he has shown in training,' said Phillips.
'For a young man, he has been excellent on the tour so far, as has Jason Robinson who also gets a chance to show what he can do with Sonny Parker now ruled out with an injury (left arm).
'We have a big task ahead of us and there is no doubt it's going to be tough.'
Wales: Rhys Williams; Mark Jones, Jamie Robinson, Mark Taylor, Tom Shanklin; Stephen Jones, Gareth Cooper; Iestyn Thomas, Robin McBryde, Gethin Jenkins, Robert Sidoli, Gareth Llewellyn, Jonathan Thomas, Colin Charvis, Martyn Williams (capt).
Replacements: Mefin Davies, Ben Evans, Chris Wyatt, Alix Popham, Dwayne Peel, Ceri Sweeney, Gavin Henson.