The problem was first reported in Australia and New Zealand, which were the first countries to ring in the New Year. And complaints have come fast and furious on sites such as Twitter. iPhone user Ameer Assik Shahrir was one of those tripped up by the bug. He had set his alarm for 7.30am, but woke up only at 8.30am. He said: "This morning, I was late for breakfast by one hour, I was supposed to meet a few friends. "If this was a school day, I would have been late by one hour and it wouldn't be good." And it wasn't good at all for those who had to work on New Year's Day. One of them called the Channel NewsAsia hotline. Alex Lam said: "I set my alarm last night for 6.30 this morning. I only received a call from my colleague at 8am, and that was when I realised I was already late for work. "I immediately went to work and noticed my colleagues were also late because their iPhone alarms also did not go off." According to tech websites, users can avoid the problem by setting the alarm to the "repeat" mode. The alarm function can apparently revert to normal on January 3. Sites such as 9to5 Mac also report that only iPhones using specific versions of the iOS 4 operating system - in particular, the 4.2.1, 4.1 and 4.0.2 versions - may be affected. However, the extent of the problem is still unclear. IPhone maker Apple has not made an official comment yet. But it had promised an upgrade of the operating system soon, following similar glitches in November when the phone's clock failed to register the switch from daylight savings time.