Wales have battled to a 17-7 victory over a spirited Tonga at the Millennium Stadium in Cardiff.

Wales coach Warren Gatland remains "very confident" of beating Australia despite an unconvincing 17-7 victory over Tonga in Cardiff.

Owen Williams and Ashley Beck scored first-half tries but a second-string Wales failed to register a single point after the 25th minute against the team ranked 12th in the world rankings.

It was far from the ideal preparation for taking on the Wallabies though the result, following a 40-6 win over Argentina, at least sends Wales into next week's clash at the Millennium Stadium on the back of successive victories.

"We're very confident about the Australia game," Gatland said.

"We were disappointed with the first game of the autumn against South Africa when we went behind but got back into it.

"We showed character in dealing with injuries which in the past we wouldn't have been able to do.

"We built on the positives for Argentina and if we can win next week then three out of four will be a reasonably good return from the campaign."

Wales will hope to have centre Scott Williams available following a foot injury, while both Owen Williams and Beck pressed their claim to face the Wallabies with tries.

It was one of the few positives on an otherwise forgettable night that barely lived up to the occasion of Gatland's 100th international as coach and a 50th Test win.

"It's a nice achievement but I'll forget the game pretty quickly and it's not a performance I will reflect on," Gatland said.

"The team is the end product and the most important thing as coaches is to try and get the best out of them and hopefully improve.

"We're not pleased with the performance and we're pretty frustrated but we're happy to win. Those are the types of games that we might have succumbed to in the past."

Wales enjoyed a staggering 77 per cent territory and 64 per cent possession throughout the game but Lloyd Williams, new cap Hallam Amos and George North all had scores ruled out by the video official.

Luke Charteris, named man of the match, was also among those guilty of squandering a catalogue of chances when he fumbled possession over the line.

Tonga's Latiume Fosita converted Will Helu's 34th-minute try for what proved to be the final score of the game.

"Defensively we were strong and we held out pretty comfortably," Gatland said.

"There were some good individual performances but it's always hard when you make that many changes and throw some young guys in for the first time and try new combinations.

"We didn't pick up any injuries either, which is always a good thing."