There are four changes (two positional) to the team that took to the field in the first Test in Sydney last weekend.
Taine Plumtree is selected at No. 8 with Aaron Wainwright ruled out of the remainder of the tour through a hamstring injury sustained in last week’s match.
James Botham comes into the starting line-up at blindside flanker. Tommy Reffell completes the back row at open-side.
Cameron Winnett is named at full-back to make his first appearance down under, Liam Williams and Rio Dyer are on the wings. Josh Hathaway is also ruled out of this fixture due to an elbow injury.
Mackenzie Martin joins the Wales replacements.
Gatland said: “We’re looking forward to getting back out on pitch this weekend in Melbourne.
“This week we’ve been going through our processes, building on what worked well and sharpening the areas that need improvement.
“We expect Australia to go up another level this weekend and we know we need to as well.
“We want to start well and make sure we are disciplined and accurate from the off. Then it’s about keeping in the arm-wrestle for the duration.”
Wales XV to face Australia
15. Cameron Winnett (Cardiff Rugby – 6 caps)
14. Liam Williams (Kubota Spears – 91 caps)
13. Owen Watkin (Ospreys – 40 caps)
12. Mason Grady (Cardiff Rugby – 13 caps)
11. Rio Dyer (Dragons – 21 caps)
10. Ben Thomas (Cardiff Rugby – 3 caps)
9. Ellis Bevan (Cardiff Rugby – 2 caps)
1. Gareth Thomas (Ospreys – 32 caps)
2. Dewi Lake (Ospreys – 14 caps) captain / capten
3. Archie Griffin (Bath Rugby – 2 caps)
4. Christ Tshiunza (Exeter Chiefs – 11 caps)
5. Dafydd Jenkins (Exeter Chiefs – 18 caps)
6. James Botham (Cardiff Rugby – 12 caps)
7. Tommy Reffell (Leicester Tigers – 19 caps)
8. Taine Plumtree (Scarlets – 4 caps)
Replacements
16. Evan Lloyd (Cardiff Rugby – 4 caps)
17. Kemsley Mathias (Scarlets – 4 caps)
18. Harri O’Connor (Scarlets – 3 caps)
19. Cory Hill (Secom Rugguts – 33 caps)
20. Mackenzie Martin (Cardiff Rugby – 4 caps)
21. Kieran Hardy (Ospreys – 22 caps)
22. Sam Costelow (Scarlets – 14 caps)
23. Nick Tompkins (Saracens – 37 caps)