Analyst Gene Munster of Piper Jaffray reckons that Apple could have shifted 500,000 iPad 2s over the weekend.
Bloomberg reports that stores contacted by Munster's team - including Apple stores and Best Buy outlets - had all sold out of the iPad 2.
"iPads are sold out across virtually all channels. We were unable to find any availability," Munster said. He added that sales could exceed his prediction that Apple would shift 5.5 million units in the first quarter tha the iPad 2 was on sale.
Apple hasn't released any official figures but the original iPad sold 300,000 units on its first day of sale back in April 2010.
The iPad 2 went on sale in the US at 5pm Pacific Time on Friday and other analysts had already predicted sales of around 500,000 - 600,000 over the weekend.
There is a three- to four-week wait for those ordering the iPad 2 through the Apple website. The device will launch in the UK on 25 March.
The future for Apple's tablet device looks strong: the predecessor of the iPad 2, the iPad, accounted for 83 per cent of the media tablet market in 2010, according to a report issued last week by IDC.
In addition to this, 82 per cent of potential tablet buyers questioned in a recent survey said that they would most likely plump for the iPad.