Apple said on Wednesday it was delaying the worldwide release of the iPad for a month, until the end of May, because of heavy US demand.
"Faced with this surprisingly strong US demand, we have made the difficult decision to postpone the international launch of iPad by one month," Apple said in a statement.
"Although we have delivered more than 500,000 iPads during its first week, demand is far higher than we predicted and will likely continue to exceed our supply over the next several weeks," the California company said.
"We will announce international pricing and begin taking online pre-orders on Monday, May 10," Apple said.
"We know that many international customers waiting to buy an iPad will be disappointed by this news, but we hope they will be pleased to learn the reason -- the iPad is a runaway success in the US thus far."
The new tablet computer from the maker of the Macintosh computer, the iPod and the iPhone went on sale in the United States on April 3.
Apple had planned to begin selling the touchscreen multi-media device in late April in Australia, Britain, Canada, France, Germany, Italy, Japan, Spain and Switzerland.
Apple chief executive Steve Jobs said last week that Apple was "making (iPads) as fast as we can." "Evidently we can't make enough of them yet so we are going to have to try harder," Jobs said.
Credit Suisse analysts have estimated iPad sales of 4.8 million units this year and 8.7 million units next year while Morgan Stanley analyst Katy Huberty forecast iPad sales of six million units this year.
The iPad allows users to watch video, listen to music, play games, surf the Web or read electronic books. It runs most of the more than 185,000 applications made for the iPod Touch and the iPhone.
The model that went on sale in the United States this month features Wi-Fi wireless connectivity, while a model offering both Wi-Fi and 3G cellular connectivity will be released in late April.
The cheapest iPad model, with Wi-Fi connectivity and 16 gigabytes of memory, is 499 dollars while the most expensive -- which includes 3G connectivity and 64GB of memory -- costs 829 dollars.