Author JK Rowling says her prized creation Harry Potter has cast his final spell.

Rowling addressed questions about Potter’s future at the Saturday gala opening of Harry Potter and the Cursed Child in London’s West End.

Fans hoping the stage production, and the publication of its script, signal the rollout of a new batch of stories, will be disappointed.

“He (Harry) goes on a very big journey during these two plays and then, yeah, I think we’re done,” Rowling said.

“This is the next generation, you know. So, I’m thrilled to see it realised so beautifully but, no, Harry is done now.”

Potter made a star of Daniel Radcliffe.

The British writer said it was not a difficult decision to put her Potter creation onstage thanks to producer Sonia Friedman’s vision for the show.

“(It) chimed perfectly with the material I had about the next generation and I could see it would work perfectly.

“So, I never wanted to write another novel, but this will give the fans something special.”

Young Harry Potter enthusiasts from around the world queued outside the ornate Palace Theatre for a glimpse of Rowling and the cast of the production.

Harry Potter and the Cursed Child, a script rather than a narrative novel, is set 19 years after Harry Potter and the Deathly Hallows and is being published at midnight on July 31.

Based on an idea by the British author and Potter creator, the play and book feature a grown-up Potter as an overworked employee of the Ministry of Magic and father of three children who is grappling with his past.

The play, which is sold out through to May 2017, opens ahead of the November movie version of Rowling’s Potter spin-off book Fantastic Beasts and Where to Find Them, and follows the opening in April of a second Harry Potter attraction within a theme park, this time at Universal Studios in Los Angeles.

With AAP