Reports are starting to emerge of battery problems with a new iPhone.

There have been several cases of batteries ‘bloating’ in the new Apple iPhone 8 Plus phones. This means the battery swells up so much it pops the case open.

Apple's problems follow Samsung's experience with its Galaxy Note 7 last year.

Hundreds of faulty Galaxy Note 7s were reported as faulty soon after that device launched ... and in some cases the phones caught fire.

The scale of the failure prompted Samsung to recall and discontinue the handset.

At the moment the Apple problems don’t seem to be anywhere near on that scale but if it happened on a plane then it would be good practice to isolate the battery in a special fire retardant bag such as an AvSax (see below) as the battery would be classed as unstable.

The BBC reports that it is not yet clear whether the swollen batteries are a few isolated cases or are indicative of a bigger issue.

The first report about an affected iPhone 8 Plus came from Taiwan. Phones with similar problems have now emerged in Japan, China, Canada, Greece and Hong Kong.

In a statement Apple said it was aware of the reports and was "looking into" what might have caused the fault. 

Apple news site MacRumours, which reported the first incident, said given the huge number of iPhones that had been manufactured it was "common" for there to be a "very low percentage of defective units." 

It added: “With millions of iPhones coming off of Apple's production lines every time new models launch it's common for a few to have battery failures. It's simply an inevitability with lithium-ion batteries. 

“It happened with some iPhone 7 models and it'll probably happen with iPhone X and whichever models come after. 

“It's only when reports of battery failure become a larger trend, as Samsung learned the hard way after dozens of Galaxy Note 7 devices caught fire last year, that it truly becomes a problem.” 

In a blog, Sam Jaffe from analysts Cairn Energy Research Advisors said battery bloat typically happened at the end of a battery's useful life. He said to have it happen soon after a product launch was troubling.

"It could be a minor distribution of a random manufacturing error," wrote Mr Jaffe.

"If it's a little bit more than that Apple might quickly be able to identify the battery manufacturing line that's responsible, shut it down and keep making iPhone 8s without any more issues."

Special fire-retardant bags called AvSax specifically designed to deal with fires in electronic devices are now on board several major US carriers.

The AvSax is used when lithium-ion batteries in mobile phones or other electronic devices catch fire.

Simply pour at least two litres of water into an AvSax and then drop the burning device into the bag. The water activates the polymer gel inside the bag causing it to expand around the device. Should the device keep on venting then the AvSax is tough enough to absorb the force.

In short, the AvSax cools the batteries in the device, reducing the likelihood of the battery catching fire but if it does go into what is known as thermal runaway it is all contained within the bag.