Australia (13) 37
Canada defended bravely throughout the 80 minutes
Tries: Baxter, Frier, Smith, Mitchell 2, Latham
Cons: Shepherd 2
Canada (0) 6
Pens: Pritchard 2
Pool B winners Australia made it four wins out of four as they laboured to a bonus-point victory over lowly Canada in the pouring rain in Bordeaux.
Tries from Al Baxter and Adam Frier helped a second-string Wallaby side into a 13-0 half-time lead.
Canada got on the board through two James Pritchard penalties either side of a George Smith try for Australia.
Winger Drew Mitchell helped himself to two tries before Chris Latham cruised over for Australia's final score.
Australia - the only nation to win the Web Ellis Trophy twice - had already sewn up the pool and took the chance to rest a host of big name players ahead of next Saturday's quarter-final against defending champions England.
The Wallabies took the lead through an early Julian Huxley penalty but struggled to put their usual free-flowing, multi-phase style of play into practice in the wet conditions.
Canada, who failed to win a match at the World Cup for the first time, were typically gutsy in defence and they lasted 23 minutes before Baxter powered over out wide.
Hooker Frier then profited as the Australian pack took charge but with Huxley missing both conversions they only led 13-0 at the break.
Pritchard's penalties gave Canada, ranked just 14th in the world, something to smile about but, despite being some way short of their best, Australia were always comfortably in control.
Smith profited from a poor Canadian line-out throw to score their third try before Mitchell went over for his quickfire brace to become the leading scorer in France with seven.
The Wallabies' final try came when Latham finished off a crisp move from first phase to claim his 11th World Cup try, joining former England winger Rory Underwood in third on the all-time list.
Cameron Shepherd managed two conversions while the Wallabies suffered a blow when number eight David Lyons was taken away in a wheelchair with what was later revealed to be a broken leg.
Australia coach John Connolly:
"It wasn't the greatest game to watch but we were happy to win.
"The conditions probably didn't help and it was one of those games we were always confident we would get away with so subsequently we were a bit loose."
Canada coach Ric Suggett:
"A credit to our players and the effort they put in. They did not slaughter us. It was not a runaway game.
"I love winning but the improvement the team has shown over the last 15 months has pleased me.
"I'm a pretty happy guy. Credit to our guys, they got stuck in. We competed very well."
Australia: Latham; Shepherd, Tuqiri, Ashley-Cooper, Mitchell; Huxley, Cordingley; Holmes, Freier, Baxter, Sharpe, Chisholm, McMeniman, Smith, Lyons.
Replacements: Hardman, Shepherdson, Elsom, Waugh, Hoiles, Gregan, Giteau.
Canada: Van der Merwe; Mensah-Coker, Pyke, Daypuck; Pritchard, Monro; Williams, Snow, Riordan, Thiel, Tait, James, Yukes, Biddle, Stephen.
Replacements: Carpenter, D Pletch, M Pletch, Burak, Webb, Fairhurst, Trenkel.