Apple will no longer release its new Apple Watch operating system watchOS 2 this week as planned after it discovered a bug in development.
A company spokeswoman said the bug was taking longer to fix than expected.
"We will not release watchOS 2 today but will shortly," the spokeswoman said. The OS had been scheduled for public launch today.
The spokesperson did not detail the nature of the bug.
The updated operating system is designed to help users customise their watch and allow apps to load faster.
Apple limited the availability of the Apple Watch earlier this year after a component supplied by a Chinese company was found to be defective.
Last year, a bug in Apple's HealthKit health and fitness application platform prevented its release along with the iOS 8 operating system for iPhones and iPads.
WatchOS 2 enables third-party applications to display information on the watch face.