Harry Potter magic hit Asia on Sunday, as aspiring witches and wizards crowded into bookstores to get their hands on the first copies of a new play that imagines the hero as an adult.

Launch parties for Harry Potter and the Cursed Child were held hours after the play's premiere in London, setting the stage for a return of the series that has captivated readers and movie audiences worldwide.

Nearly 300 fans rushed through the doors of Kinokuniya bookstore on Singapore's Orchard Road at 7:01 am to become one of the first people in the world to see the new script.

Student Samantha Chua, 24, who along with her boyfriend was first in line, said she had been waiting outside the fourth-floor bookstore since 5 am.

"We were here so early that the mall wasn't even open yet so we had to come up through the cargo lifts," she said, adding that it was "all worth it".

"I grew up reading the books and I have a special place for them on my shelves but this will be my crowning glory," added Chua, who was wearing a Harry Potter-themed sweater.

Widely seen as the eighth Harry Potter installment, the play is set 19 years after the end of the last book and features a grown-up Potter working at the Ministry of Magic.

Like many of his fans, Potter has now become an adult and has three children with his wife Ginny Weasley.

He still has his trademark round-rimmed glasses and the scar on his head, a permanent reminder of his nemesis Lord Voldemort, but must now help his youngest son Albus confront the family's dark past.

The script's global kickoff was timed to coincide with its launch at midnight in London, after the play's world premiere at the Palace Theatre earlier in the evening. July 31 is also author J.K. Rowling's birthday.

In India, fans began lining up outside shops which had opened early especially for the script's release.

"It's been amazing to see 10-year-old fans and 70-year-old grandmothers turn up at our shops," Shilpi Agarwal, a spokeswoman for Om book shops, said in New Delhi.

"We've got an excellent response," she told AFP, adding that the store would be laying on Potter-themed activities throughout the day.

In Bangkok, around 40 fans, many wielding wands and other wizarding paraphernalia, gathered outside a large downtown mall overnight.

Sanpipat Huangsawat, 29, was first in line and had started queuing at 6:30 pm on Saturday evening. He finally got his hand on the book some 11 hours later.

"I feel very excited and it's great to be the first owner of this book in Thailand," he said.