A grocery commentator says new players like Costco are one part of the puzzle, of adding grocery competition

The US big box retailer says, it's "working on" how it can extend to other centres.

The Government's indicated it'd welcome expansion.

Grocery commentator Ernie Newman also wants the Government to look at other things -- like forcing Woolworths and Foodstuffs to sell off some of their stores.

He says there needs to be change in the next year or two, not a generation down the track.