Amazon sees a future where we can walk into a store, grab what we need and leave without facing lengthy queues at the checkout. The e-commerce giant's Amazon Go stores offer just this, with an array of clever tech removing the need for cash or cashiers and making picking something up from the shop literally as easy as picking something up from the shop.

But the company is apparently facing some technical hurdles in making a staff-free store a viable concept, in that the technology used to make the concept work isn't able to handle the demands of your typical gaggle of weekend shoppers.

The first Amazon Go shop opened near the online retailer's Seattle headquarters in 2016 and sells pre-prepared meals, alcohol and other groceries. On entering, shoppers scan themselves using their smartphone and from there a combination of cameras, sensors and machine learning tech tracks what each customer takes from the shelves.

Upon exiting the store, the total value of the items is tallied up and charged directly to the customer's Amazon account, eliminating the need to pay for the goods in-store.

Yet according to the Wall Street Journal, the technology struggles to accurately track what's leaving the shelves when there are more than 20 or so people in the store at one time. It also has difficulty keeping tabs on items if they're picked up and then left somewhere else, or moved from a specific spot on the shelf, as often happens in supermarkets. This is particularly problematic when in promotional material for Amazon Go, Amazon specifically declares that picking up an item and putting it back if you change your mind isn't a problem.

Amazon not a Go

As it stands, the only situation where the technology works "flawlessly" is when there are fewer than 20 people in the shop who are moving around slowly, a source told WSJ. Subject it to the frenzied crowd of a standard supermarket, and the system crashes. Amazon expects big crowds in its high street stores when they open, so this is major problem for the company.

The wider opening of Amazon Go stores in the US and further afield is reported to have been put on hold until the kinks can be ironed out. Amazon had previously suggested its brick-and-mortar convenience stores would begin opening doors in early 2017, yet with Q2 just around the corner that particular launch window is rapidly narrowing.

Alongside groceries and book stores, Amazon is also said to be planning physical home furnishing stores that would take on high-street favourites like Ikea and may employ augmented reality technology to help customers see how an item would look in their home before they buy it.

IBTimes UK has contacted Amazon for comment.