The book is on offer on Amazon's US, UK, Canadian, French, German and Japanese sites.
However, with less than three weeks to go it is far from certain that the sixth book in the series will surpass the record 1.3 million pre-orders of its predecessor, Harry Potter and the Order of the Phoenix. UK pre-orders for the fifth title reached 420,000, compared with 200,000 quoted by Amazon for the latest book, due out on July 16.
A spokesman for Amazon.co.uk said the company would not give out a forecast for final pre-order numbers, but said the retailer was expecting a very busy three weeks. The UK price for the book has been reduced to£8.99, which should encourage further orders.
US orders reached 560,000 last week. It is priced at US$17.99 (£9.86).