Hamilton Written off before the tournament began, India have waltzed into the playoff stage of the World Cup with the swagger of defending champs.

The 2011 winners defeated Ireland by eight wickets at Hamilton's Seddon Park on Tuesday night to seal top spot in Group B and most likely set up a quarterfinal against Bangladesh.

The champs were threatened briefly during a spirited Irish innings in perfect conditions, but after India's spinners slowed the underdogs, their seamers picked up late wickets as Ireland were bowled out for 259 in 49 overs.

India got that in a canter, barely registering a sweat when pulling up past the post with 79 balls to spare.

Nothing the limited Ireland bowling attack attempted against India looked the least-bit threatening as openers Shikhar Dhawan and Rohit Sharma put on a record first-wicket stand for India in World Cups of 174 to erase any thought of another shock result from an Ireland side that had upset the West Indies in their opening fixture.

Dhawan made his eighth one-day international ton before falling soon after for exactly 100, made from only 84 balls and featuring five sweetly-struck sixes and 11 fours. The left-hander has been one of the form batsman of the tournament - only Sri Lankan legend Kumar Sangakkara has scored more runs - and has now compiled 333 runs from five digs at an average of 66.60.

Sharma made a complimentary 64 off 66 balls, including three sixes and three fours, before playing on to Stuart Thompson to give Ireland a little joy.

While India romped into the last eight - they finish pool play with a match against Zimbabwe at Eden Park on Saturday - Ireland were left needing a win in their final group match against Pakistan in Adelaide on Sunday to qualify for the playoffs.

India's bowlers were supposed to be their Achilles heel, but they've managed to dismiss their opponents in all five matches in pool play.

There appeared to be concerns over the effectiveness of their seamers when Ireland went on the attack early - William Porterfield (67) and Paul Stirling (42) flourished initially after Ireland  won the toss and elected to bat.

The duo were quick to climb into anything short on a reliable track as they took to the Indian new-ball combination of Umesh Yadav and Mohammed Shami.

With the early run-rate above seven, Indian skipper MS Dhoni was forced to bring on his spinners before the completion of the first 10 overs.

The guile of Ravichandran Ashwin and the flatter deliveries of Ravindra Jadeja and Suresh Raina soon pushed Ireland onto the back foot.

Part-timer Raina bowled 10 overs while taking 1-40 while Ashwin's first eight overs went for just 18 before he ended with 2-38 off his full complement.

Niall O'Brien made 75 from as many deliveries, featuring three sixes and seven fours, and had Ireland poised for a very handy tally, but they lost their last seven wickets for 53.