Wales and the Wallabies have been drawn in the same pool for the tournament in Japan next year, having also faced off in the first round in 2015.
Michael Cheika’s men kick off their tour of the northern hemisphere at the Principality Stadium this weekend but arrive on the back of a poor showing in the Rugby Championship, which they ended with two wins from six matches.
But centre Roberts, who has 94 caps to his name, believes coach Warren Gatland should not read too much into the Australia side that turns up this weekend.
“It’s a long way out. I don’t think you can look at the performances in November and make any indication of how teams will go at the World Cup,” he told Omnisport, speaking on behalf of Land Rover.
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“It always throws up a few surprises. Players get injured, others will come into form, teams will work out how exactly they want to play. There’s a lot of rugby to be played.
“Everything changes and it’s the teams who build a good strength in depth, have a real identity and work hard at what they want to achieve, who do well at World Cups.”
— Welsh Rugby Union ? (@WelshRugbyUnion) November 5, 2018
Wales and Australia will be joined by Georgia, Fiji and Uruguay in Pool C for the tournament, which begins on September 20.
“One thing Australia do well is peak for World Cups. They’re a b***** good side,” added Roberts.
“It’s a hugely competitive group Wales have and there’s no doubt a lot of hard work is going into preparing that Welsh side ready for the World Cup.
“It’s always a fantastic occasion. Having played at the last two World Cups and making a semi-final and quarter-final, Wales have a great opportunity in Japan, there’s no doubt about that.
“When I look at the Welsh squad and I look at what we’ve built over the last few years, the strength in depth we have in almost every position is encouraging and certainly stands us in good stead.
“But as far as Australia go, they’re a side who on their day can beat any side in the world, they’re hugely competitive and have a knack of peaking at every World Cup.”
Roberts is not part of the Wales squad for the November internationals, which started last weekend with a 21-10 victory over Scotland.
And while he concedes that forcing his way into contention for a World Cup place will be at the back of his mind this season, his primary concern is playing regularly for new club Bath.
“My main focus is to win games with Bath and be diligent as a professional every day, making sure I’m doing everything I can to become a better player,” he said.
“If that’s good enough to win me a starting spot with Bath, help me perform to the best of my abilities, impress and get me selected for Wales, then so be it.
“It’s definitely a long-term goal of mine to play in that World Cup. I’d love to get back in that squad.
“It’s the goal of most Welsh rugby players this season. I’m just one of those players chasing that dream.”
Jamie Roberts was speaking on behalf of Land Rover, the Official Vehicle Partner of Bath Rugby. @LandRoverRugby
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