The Warehouse is advising customers on its website deliveries could take up to two weeks to arrive.
It said while it was trying to get through orders as quickly as possible, because of the high number of orders it was struggling to keep up.
"Orders with multiple items may be delivered as separate packages," The Warehouse said on its website.
"We're shipping orders as fast as we can, however some may be delayed and take between 10-14 days due to unprecedented demand."