Coles bets bigger is better with 'super size' trial

Supermarket giant Coles is betting that bigger is better as it super-sizes its wares to compete with bulk retailer Costco.

From tomorrow, Coles will be offering bulk purchases of its goods - everything from Nutri-Grain to soy sauce.

Coles senior communications manager Martine Alpins said customers would see savings of more than 60 per cent in some cases, and up to 40 per cent in "a lot".

"Over winter our customers love to stock up on staples," she said.

"Things that you don't want to have to keep buying at the supermarket. You can buy once and have it there ready to go for your family.

Melbourne mum Micah Webb told A Current Affair she welcomed the changes.

"I think it gives us the opportunity as mums to spend less time in the shop and more time at home with our families," she said.

Examples of savings include $5 for a 1kg bos of Panko bread crumbs, which normally sell at $2.70 for 200 grams - a 63 per cent drop.

A 2kg pack of San Remo couscous saves 46 per cent on the standard price, and a five-kilogram bag of Barilla pasta costs $14 - a saving of 28 per cent.

Rival Woolworths is also making a play to win customers, today announcing a 24-hour online sale with 50 per cent off selected products.

Coles' super-size trial will run nationally, while stocks last.