Apple said on Wednesday it would delay for one month the international roll-out of its iPad tablet computer, due to heavy demand and swift sales after its launch in the United States.

"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 as more people see and touch an iPad," Apple said. "We have also taken a large number of pre-orders for iPad 3G models for delivery by the end of April."

"Faced with this surprisingly strong US demand, we have made the difficult decision to postpone the international launch of iPad by one month, until the end of May," Apple added.

Apple plans to announce international pricing and begin taking online pre-orders on Monday, May 10. Vodafone Group today also said it will offer iPad price plans from the end of May in Australia, Germany, Italy, Spain, and the Britain.

In the United States, the device has proven more popular than expected, selling 500,000 units in the week after its April 3 launch.