Some iOS 7 users have experienced problems with iMessage, but Apple has reassured their fans that the issue will be fixed in an update.

Only a "fraction of a percent" of users have been affected by the problems, which drew complaints as some people said iMessages did not send and that there was no indication that the messages failed to deliver.

"We encourage any users having problems to reference our troubleshooting documents or contact AppleCare to help resolve their issue," Apple said. "We apologise for any inconvenience this causes impacted users."

Several people posted on the Apple support forums as they expressed their frustration.

"All messages don't send through iMessage and I have to resend the messages as text messages in order for them to go through," one person said. "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 user echoed those concerns.

"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 ..."

iOS 7.0.2 is already out and Apple has been working to address a variety of complaints that have been posted on the support forums. A number of users had said that the iOS 7 operating system was making them sick after the animations caused motion sickness.