Apple has admitted there is a glitch with its iMessage feature on the new iOS 7 operating system and has promised to solve the problem with a new update.
The company apologised to those affected but stressed that only a "fraction of a percent" of iMessage users were affected by the issue.
After the launch of iOS 7 last month people posted complaints about Apple's messenger service – which sends texts over the internet rather than via the phone network – on Twitter and the company's own online support forum.
Some users said that texts sent via iMessage failed to get delivered and warned that no indication was given that the message had not got through. Others found that by turning on and off the handset the problem would temporarily disappear before eventually returning.
One complaint wrote on Apple's support forum: "All messages don't send through iMessage and I have to resend the messages as text messages in order for them to go through. If I restart my phone, for some reason that helps with messages being sent as iMessage, but after a while, it goes back to not working."
Another wrote: "I've turned my phone on and off at least 9 times and have reset my network settings multiple times within the last week. This is not a suitable workaround ..."
In a statement given to the Wall Street Journal the company acknowledged there was a glitch affecting some iMessage users and promised to resolve the problem.
"We are aware of an issue that affects a fraction of a percent of our iMessage users, and we will have a fix available in an upcoming software update,” a spokesman said.
"In the meantime, we encourage any users having problems to reference our troubleshooting documents or contact AppleCare to help resolve their issue. We apologise for any inconvenience this causes impacted users."
The much-anticipated arrival of iOS 7 has been dogged by a series of security glitches and unexpected problems which have threatened to overshadow praise for the redesign.
People attempting to download the software onto old Apple devices complained of long delays, while some of those who got the update said the new interface made them feel sick.
Security concerns were raised when videos posted online showed how would-be hackers could get around an iPhone lockscreen without a password, accessing sensitive personal information.
It was also discovered by one German hacking group that the fingerprint security in the iPhone 5s, which runs on iOS 7, could be cracked by using lifted prints.
Some of the glitches were fixed in iOS 7 updates already rolled out while the above statement from the company confirms another is in the pipeline. In the past Apple has stressed how seriously it takes security issues when asked for comment on glitchs concerning personal information.