Ireland overtook Australia at the top of Pool C with a comprehensive 36-6 win over Italy in their World Cup match at Otago Stadium on Sunday.

Ireland were up 9-6 at half-time, but emerged from the break looking to stamp their authority on the contest, and two tries in five minutes - first from Brian O'Driscoll and then from Keith Earls - put the game beyond doubt.

Earls crossed late for a second try that Jonathan Sexton converted, while fly-half Ronan O'Gara was also on song for Ireland, slotting two conversions and four penalties.

Italy competed well in the first half but the pace of the match told on them in the second as they missed out on their dream of becoming the first Azzurri team to qualify for the quarter-finals.

Ireland will now meet Wales in the quarter-finals after finishing pool play on top of the group with 17 points, ahead of Australia (15) and Italy (10).

O'Gara opened proceedings for Ireland when he kicked a penalty goal from an acute angle after seven minutes.

Italy was combative in the scrums, drawing a penalty themselves which Mirco Bergamasco converted to level the scores.

Ireland again made it a three-point margin when O'Gara kicked a penalty from a lineout, before Bergamasco leveled once more with his second penalty after a collapsed Irish maul.

Neither side was able to gain any significant ascendancy but O'Gara regained the lead for Ireland with a penalty from in front after 34 minutes and Italy suffered a blow when prop Martin Castrogiovanni limped off with injury and was replaced by Andrew Lo Cicero.

Italy had a chance to level the score on the stroke of half-time but referee Jonathan Kaplan reversed what would have been a comfortable penalty when an Italian forward threw a punch.

Ireland had 59 percent territory in the first spell and had forced Italy had to make 43 tackles to 27, but the Azzurri had also looked dangerous when they mounted some powerful forward drives.

Ireland extended their lead to 12-6 three minutes into the second half when O'Gara kicked his fourth penalty when an Italian forward did not roll clear of the ball at a ruck.

It was Tommy Bowe who finally cracked the Italian defence seven minutes in when he ran at an angle, broke a tackle and O'Driscoll took the in-pass and scampered 20m to the posts.

O'Gara converted and it was 19-6.

Ireland were rampant and they scored again five minutes later, left wing Earls diving over in the corner after excellent continuity which was started by a thundering run by Gordon D'Arcy.

O'Gara converted expertly and Ireland had scored 17 minutes in 12 minutes after the break.

Ireland had dominated the third quarter almost completely as they lifted the tempo and imposed severe pressure on the over-worked Italian defence.

The lead became 23-6 when Sexton, who had been substituted in for O'Gara, kicked a penalty from 32 metres out.

Ireland made victory even sweeter in the final minute with a beautifully-taken try by Earls in the left corner which was converted by Sexton.