The Commerce Commission is ramping up efforts to disrupt the supermarket monopoly. 

It says supplier charges and promotional pricing are reinforcing the dominance of Foodstuffs and Woolworths. 

It's proposing a simplified grocery code, reducing the range of payments that supermarkets can charge suppliers. 

Grocery expert Ernie Newman told Ryan Bridge that supermarkets are receiving billions of dollars in discounts - which largely aren't being passed on to consumers.  

He says there's more money floating around in the sector than the Commerce Commission had previously identified. 

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