Excitement mounted among Harry Potter fans worldwide Friday as the clock ticked down to the release of the last instalment of his adventures, but a growing tide of leaks threatened to mar the event.

With only hours to go before the 2301 GMT publication of "Harry Potter and the Deathly Hallows" in most of the world, queues grew outside bookstores which were braced for a record demand for the seventh, swansong Potter tome.

And the frenzy surrounding the launch triggered a last-minute price-war as booksellers sought to get a bigger slice of the massive market for the book, which will finally reveal whether or not Potter dies.

"Harry Potter has reignited children's passion for reading," said a spokesman for British supermarket ASDA. "Our colleagues and customers are gearing up for the biggest book launch we've ever seen."

The book's initial release time is a minute past midnight in Britain, the home of boy wizard Potter and the setting for his adventures.

In Asia, all-night parties and Hogwarts Express-style train trips were among the hundreds of events planned.

Selling frenzy

In Muslim Bangladesh, where Friday is a holiday, customs offices stayed open specially to ensure fans got their books on time, while in Thailand the British ambassador was planning an early start to hand over the first copy of the book.

In Malaysia there was also a price-war, leading four major bookstores to boycott its sale. Some outlets were offering the book at RM69.90 (US$21).

In Britain the lowest price was 4.99 pounds (around US$10), after Morrisons supermarket trumped rival ASDA's five pounds offer by one penny.

But despite the anticipated selling frenzy, the book's worldwide release was marred for some by the controversy over plot leaks which emerged despite tight security surrounding the book.

Author JK Rowling said Thursday she was "staggered" by the publication of reviews by The New York Times and others, and urged fans to "ignore the misinformation" circulating about the plot.

The book's US publisher Scholastic also said Thursday that it would take legal action against a distributor and a retailer who sent hundreds of copies to readers in advance of the release - which in the US, Canada and Mexico, is later than the rest of the world, at midnight local time.

The New York Times review, written from a copy bought in the city on Thursday, revealed that at least six characters die in the book, although it did not say which ones, amid fevered speculation that Potter himself could be among them.

The review describes the final pages of the book as "a big-screen, heart-racing, bone-chilling confrontation" and says it contains "an epilogue that clearly lays out people's fates."

For their part, several British newspapers either re-printed the review in full, or summarised it.

Will Potter live?

But leaks appeared in a number of other countries on Friday, with papers in France, Italy, Austria and the Czech Republic revealing the fate of key characters by printing a summary of the epilogue some of them upside-down so that unwary readers could avoid the spoiler.

The six Potter books so far released have sold 325 million copies internationally and have been translated into 64 languages, though the final tome is set to out-sell each of its predecessors.

Rowling is hosting a reading and signing with fans at London's Natural History Museum overnight Friday, while hundreds of British bookshops are hosting after-hours parties to which fans are likely to flock.

Having conceived of the story while on a train from Manchester to London, she wrote the first book as a single mother receiving state benefits, and has made an estimated US$1 billion from the works, the first of which appeared 10 years ago.

British charity ChildLine said it was bracing for a surge in calls from distraught children after the final book is released, warning that the expected death of a key character would spark feelings of loss and bereavement.

British bookmakers Ladbrokes and William Hill have stopped taking bets on Potter's fate.