Who is really saving money when supermarket shoppers check out and bag their own groceries?

That is a question New York lawmakers have reportedly been pondering.

State representative Nikki Lucas has introduced a bill that would require retail businesses selling food in the state to offer a 10 percent discount to those who used the self-checkout lane.

"Retail businesses increasingly rely on self-checkout systems to reduce staffing and operational costs by shifting responsibilities traditionally performed by employees onto consumers," she wrote.

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"Since customers are effectively completing portions of the checkout labor themselves without compensation, providing a mandatory discount helps ensure fairness, acknowledges consumer participation in store operations, and allows the public to share in the financial savings created by self-service technology."

Consumer NZ head of advocacy Gemma Rasmussen said her organisation thought there was validity to the argument in New Zealand, too.

"If you're serving yourself then ultimately the supermarket is saving money through less staff resourcing, and those savings are not currently being passed on to shoppers.

"Pak'n Save advertises themselves as a cheaper place to shop given you pack your bags yourself. It seems many businesses are moving towards fewer staff and more technological assistance, for example there are now fewer bank branches across New Zealand, and more chatbots instead of call centre representatives across a number of major businesses. Ultimately this provides a cost saving for the business, not the consumer."

She said concern about the price of food and groceries was still the number one financial worry for most people.

"When we started tracking financial concerns in 2022, food pricing was the 8th highest concern. Lowering prices for shoppers who choose to self-serve would be one way to alleviate some of these cost pressures, however we're dubious the supermarkets would introduce such a discount."

University of Auckland marketing expert Professor Michael Lee said it made sense from a fairness point-of-view.

"The supermarkets are saving ongoing cost of labour by automating that portion of their operations. Therefore, why not to pass on the savings to their loyal customers?"

He said in a market like New Zealand, it was unlikely that retailers would make the choice to offer a discount, unless they were compelled to.

"Unless one of the retailers, or a new entrant, decided to take this approach, there would little incentive for either to do so, meaning that the two main retailers would continue to use such cost savings to extend their profit margin."

Foodstuffs said self-checkouts were one of a number of ways customers could choose to shop, alongside traditional staffed checkouts.

"Many customers value the convenience, speed and flexibility that self-service offers, particularly when buying a small number of items. We continue to invest in both self-service and staffed checkouts so customers can choose the option that best suits their needs. Team members are always available to assist customers using self-checkouts and to operate staffed lanes. Our focus is on giving customers choice and making shopping as easy and convenient as possible."

Woolworths was also approached for comment.