Apple has received a record four million pre-orders for its new iPhones in 24 hours.

The number exceeds the pre-order supply, meaning many people will have to wait until October for their new handset to arrive, the company says.

In-store sales of the iPhone 6 and the iPhone 6 Plus open on Friday morning around the globe.

Time zone differences mean Australian stores will be among the first in the world to open their doors on the day.