Australia have secured a quarter-final spot at the Rugby World Cup after a 68-22 thrashing of Russia in their pool C clash on Saturday.

The Wallabies scored 10 tries with James O'Connor kicking the last nine conversions in the victory, which took them to the top of their pool.

The result means Ireland must overcome Italy in Dunedin on Sunday to be top qualifier and avoid a quarter-final showdown with defending champions South Africa.

But Russia earned plaudits by scoring three tries and restricting Australia to 21 points in the second half while adding 17 points themselves.

As befitting the world's third-ranked team against the 21st, Australia dominated the key areas early and Russia's poor defence allowed the Wallabies to display their backline attacking finesse.

But the Bears were more committed in the second spell, gaining more possession and forcing Australia into errors.

Australia's first try came in the seventh minute after flanker, Radike Samo, playing on the right wing, burst the first tackle to set up a try for inside centre Berrick Barnes. James O'Connor missed the conversion.

From the restart, Australia had their second try after half-back Luke Burgess broke in midfield and Barnes placed a kick ahead which left wing Drew Mitchell easily gathered with no defence in sight.

O'Connor converted from the sideline for a 12-0 lead.

Try three also came from the kick-off, Samo claiming a little kick to his wing and linking with his forwards for No.8 Ben McCalman to score a well-worked try unopposed by the posts, giving O'Connor an easy conversion.

The bonus-point try came in the 15th minute from a line-out win, flanker David Pocock standing off and brushing through two weak tackles to score under the cross-bar, O'Connor kicking his third conversion for a 26-0 lead.

Pocock claimed his brace after 22 minutes after the Russians again fell off tackles and O'Connor's conversion extended the lead to 33-0.

Russia went close to scoring after 31 minutes, half-back Alexander Yanyushkinbeing held up on the line, but wing Vladimir Ostroushko was not be denied a minute later when Australia spilled the ball on a counter-attack.

Ostroushko beat a tackle in a touch-line sprint, scoring too wide out for Yury Kushnarev to convert.

Australia hit back with a try to hooker Stephen Moore after a clever no-look backward pass by Mitchell, O'Connor again having an easy conversion.

Australia had try number seven a minute before half-time, centre Adam Ashley-Cooper being first to a little grubber-kick by Quade Cooper. O'Connor converted from wide out to give the Wallabies a 47-5 lead at the break.

Australia posted its half-century with a try to prop Salesi Ma'afu two minutes into the second spell, O'Connor kicking a seventh successive conversion.

Russian replacement first five-eighths Konstantine Rachkov dropped a goal from in front after 46 minutes and that was a forerunner to Australia's ninth try, wing Mitchell diving over for his second after a quick penalty caught Russia unawares.

O'Connor converted from the sideline for a 61-8 lead.

Mitchell pulled his left hamstring when heading for his third try, the wing being replaced by half-back Nick Phipps.

Big Russian wing Denis Simplikevich intercepted a Cooper pass and ran 35m to score under the bar for Rachkov to convert on the hour as rain set in.

Rachkov was over for Russia's third try after 68 minutes when the Bears went for a line-out after a penalty and drove to the line before Rachkov surged across. He added the conversion from a sharp angle to take the score to 61-22.

A charge-down by Barnes led to his second try with time nearly up, O' Connor kicking his ninth conversion.