Vodafone, Orange and O2 are preparing price plans for the iPad 3G in the UK
Apple is to delay the international release of its touchscreen tablet computer, the iPad, by one month.
It will now launch the device around the world, including the UK, at the end of May, and will begin accepting pre-orders on 10 May.
In a statement the company blamed demand for the device in the US, which it said had been "surprisingly strong".
When the iPad launched in the US, 300,000 units were sold on its first day.
Apple claims it delivered 500,000 in the first week of its release.
"Demand is far higher than we predicted and will likely continue to exceed our supply over the next several weeks," said Apple.
Prices for the first iPad models start at $499 (£328) in the US. They have wi-fi but not 3G connectivity.
In the UK mobile phone providers Vodafone, Orange and O2 are already preparing price plans for the 3G version, which will require a separate micro-SIM card in order to connect to the net. Existing mobile phone SIMs will not work with the device.
Hundreds of new iPad owners in the US complained about connection problems on the Apple support page shortly after the launch of the device on 3 April.
Apple suggested a fix but problems are still being reported.
"Nothing works. It connects when it wants and the bars go up and down when I sit in the same spot in my house," wrote Phillies2009 on 13 April.
Analyst Ian Fogg from Forrester Research told BBC News that Apple's reason for the delay was "credible".
"The iPad is in a new category of devices - for that reason I think it would have been very hard for Apple to have accurately predicted sales before launch," he said.
"There is a possibility of manufacturing or component problems but it's more likely that they simply didn't forecast demand."
He added that most electronic devices, including mobile phones and games consoles, stagger their product launches around the world.
Stuart Miles runs technology review website pocket-lint. He thinks that the delay might not work in Apple's favour.
"The sales figures show there is an appetite for a touchscreen device, but the longer they leave it the more chance other manufacturers have of getting in on the game," he said.