Apple sold nine million iPhones in the weekend debut of two new models, almost double the previous record, alleviating investor concern about a prolonged slump at the world's largest technology company.

Sales reached record territory even amid supply constraints for the iPhone 5s, the higher-end version of the two handsets, Apple said yesterday in a statement.

The results also led Apple to say that quarterly revenue and gross margin will be at the top end of a prior forecast.

"While we've sold out of our initial supply of iPhone 5s, stores continue to receive new iPhone shipments regularly," chief executive Tim Cook said in the statement.

“We appreciate everyone’s patience and are working hard to build enough new iPhones for everyone.”

Apple’s shares rose as much as 6.3 per cent, the biggest intraday jump since November, as the sales exceeded even the loftiest analysts’ projections of less than eight million.

The iPhone is Apple’s most important product, accounting for half its sales. – (Bloomberg)