Harry Potter hype is helping sales of other Bloomsbury books, as the publisher gears up for record sales of the sixth tale about the boy wizard.

Bloomsbury chairman Nigel Newton told shareholders at the company's annual meeting yesterday that the company had made "good progress" since the beginning of the year.

The publishing house will launch its biggest advertising campaign on Monday as part of the build-up to the worldwide release of Harry Potter and the Half Blood Prince. The book will be launched at Edinburgh Castle at one minute past midnight on Saturday July 16, when author JK Rowling reads to an audience of children. The reading will be beamed around the world.

Bloomsbury has refused to provide details of print runs or sales expectations. But anecdotal evidence suggests it will break the 1.7m first day record set by the last instalment, The Order of the Phoenix.

Even before the advertising campaign has begun, Amazon has received 500,000 pre-orders, Barnes & Noble has registered 750,000, and Tesco said last week its website was receiving one every minute.

The initial print run in the US is 10.8m copies, compared with 8.5m for Harry Potter 5.

"All in all HP6 looks set to live up to all expectations," Dresdner Kleinwort Wasserstein said in a note to clients. "Any concerns that HP6 will not deliver look totally misguided."

Mr Newton said Harry Potter fever had also stimulated sales of earlier books in the series.

Analysts believe the Harry Potter juggernaut is buoying other Bloomsbury titles.

Mr Newton reported strong sales of The Promise of Happiness by Justin Cartwright. The company has also had two bestsellers in Germany.

Bloomsbury is planning to increase the number of books it publishes in the US next year following the integration of Walker Publishing Company.

Analysts said Bloomsbury was now well positioned for growth in the world's largest book market.

Pre-tax profit of £20m is expected this year, up from £16.4m in 2004.

Bloomsbury shares fell 6p to 376.5p yesterday.