Prime Minister Jacinda Ardern and Commerce and Consumer Affairs Minister David Clark were given a tour around NZ's first Costco megastore in Auckland on Thursday.

It comes as the Government on Wednesday confirmed a wholesale plan to try and drive food prices down.

Clark says the introduction of a new player into the market will be good competition for the supermarket duopoly.

"The analysis from the Commerce Commission that has been done on the grocery sector indicates that their is room for improvement on the competition front and here we have a company that is really interested in doing that."

Costco in Auckland (Source: 1News)

The West Auckland store was initially slated to open mid-August, but that has been pushed back due to "inevitable hurdles".

"Our builders had numerous delays with materials coming in late offshore. We've had delays with Covid on site and we've had a wet few months, so everything sort of added up together that we needed a few more weeks to get the job done," Costco managing director Patrick Noone told RNZ.

Costco is a large US retailer famous for bulk groceries, as well as other items.

When plans for the first Auckland store were announced, a retail industry expert said Kiwi consumers can expect big discounts.

Auckland's Costco before it opened (Source: 1News)

"Costco will be 30% cheaper on average for most products, and will have a wide range of goods from household products to catering supplies through to coffins and petrol and tyres.

READ MORE: Prepare for 'more pain' at the supermarket - agricultural analyst

"It's like The Warehouse on steroids would be the way I describe it - huge in scale and huge in range," Chris Wilkinson from First Retail Group said.

Costco runs on a membership system, with costs starting at $55 for a business membership.

Watch the video above to see how the progress is coming along on the $100m flagship store.