Owners of the new foldable iPhone are reporting cracks in the device’s screen, as Apple confirmed an issue with a “small number” of units.

Reports of cracks have emerged on Reddit and social media platforms since the handset went on general sale globally on Friday. Experts said there had been too few examples to determine whether there was a more serious problem with Apple’s first foldable device, which retails from $1,999 (£1,499).

Apple confirmed some devices had been affected by a display glitch.

“We are aware of an issue impacting the inner display on a small number of iPhone Duo units. If users experience issues with their iPhone Duo display, they should contact AppleCare for a replacement,” it said.

One user in Australia reported that their Duo had cracked within six hours of taking ownership of it and posted their experience on Reddit.

“I was showing it to a friend, and as I opened it, I felt something around the internal hinge, underneath the screen,” they wrote alongside an image of the phone showing an apparent display malfunction where a white strip of light ran along one half of the screen.

“As I continued opening it, I heard an audible crack, and the screen broke right along the hinge.”

They said their local Apple store had replaced the phone immediately. The Guardian has been unable to verify the user’s claims. Another user in Australia posted that they had heard “almost a cracking noise” on their handset, which resulted in a similar screen malfunction.

A report by the Bloomberg news service also highlighted similar issues among users in the US and India.

Apple believes the affected units are showing defects quickly after use. It said the response from early users had been “incredibly positive”.

The company said demand had been “nothing short of extraordinary” for the iPhone Duo, its most high-profile product launch under the company’s new chief executive, John Ternus, who took over from Tim Cook in September.

The device has sold out and the next round of shipments is not expected until January, according to a report in the Economic Daily, a publication based in Taiwan, the home country of Foxconn, Apple’s main device manufacturer.

Francisco Jeronimo, the vice-president of data and analytics at IDC, a tech research company, said it was too early to tell whether the screen issue was significant. “This is quite common when a new product comes to market,” he said.

Citing similar problems at Samsung in 2019, he said: “What matters now is how the company responds … Samsung experienced problems with the original Galaxy Fold in 2019, but it also showed that a fast and transparent response can contain the damage to a category.

“Apple said that any customer with problems should ask for a replacement, which is the right first step.”

Ben Wood, the chief analyst at the research firm CCS, said he was taking a very cautious view of the Duo screen problem and that there was as yet no evidence of a more widespread issue with the device.