It looks like Apple's potential stock shortages on its Watch are because of ridiculous first day sales with around 1 million pre-orders in the US.

Consumer spending tracker, Slice Intelligence, studied 9,080 US online shoppers and says Apple sold around 1 million Watch units on the first day of pre-orders last Friday 10 April.

Apple Watch sales were phenomenal with most of them reaching sold out status within minutes of going up for pre-order online in the US. The result is that a lot of models now have a waiting period of at least a month before they're back in stock and can be shipped.

The most affordable of the Apple Watch models, the Watch Sport in 42mm size with white band, sold so quickly US buyers won't be able to get hold of one until June.

Apple's popularity appears to have been an international event with sold out notices on its sites in China and Japan.

According to the data studied by Slice Intelligence the most popular Watch was the most affordable Sports while the $10,000 Edition models sold so few they didn't even appear in the data. The most popular colour was Space Gray followed by Stainless Steel. Of the bands the black was the most popular representing almost half of all orders. A total of 72 per cent of the pre-orders were for the lager 42mm model.

Rather interestingly 43 per cent of Apple fans that bought a new MacBook also bought an Apple Watch.

The Apple Watch will officially go on sale from 24 April. But since Apple has confirmed that customers can't buy a watch in store it looks like there'll be a wait for everyone.

READ: Apple Watch: You won't be able to buy in Apple store on day one