Instagram users could soon be able to instantly buy their favourite on-screen items.

The photo and video sharing service, used by more than 500 million people across the world, is to start tests for the shopping feature on applications on Apple mobile devices in the US next week.

Twenty American retailers, including Kate Spade, JackThreads and Warby Parker, will take part in the e-commerce test, sharing posts with 'Shop Now' icons.

These will allow users to purchase items featured without having to leave the app to search.

In a blog post, Instagram bosses said the aim was to provide "the most seamless shopping experience for consumers".

"Mobile has changed the way people shop," Instagram said in the post. "We're excited to announce an easier experience to shop the products you love on Instagram."

Instagram, which is owned by Facebook, cited industry statistics indicating that smartphone apps and web browsers are commonly used in America to browse or research options regarding potential purchases.

JackThreads chief marketing officer Ryan McIntyre said the new technology would "change the scope of what we, as retailers, are capable of offering on mobile".

He added: "Our customers will be able to shop seamlessly from their social media feeds - allowing us to reach guys where they're already hunting for what's new."

The announcement comes just days after rival Twitter announced it will be closing video sharing app Vine and axing almost one in 10 jobs worldwide.