The sensation caused by the mainland blockbuster Ne Zha 2 is very much a "lightning in a bottle-style success" which may not be easy to replicate, according to a local film critic.

The animated film, based on the mythological character from Chinese folklore, hits the big screens in Hong Kong on Saturday, after smashing box office records on the mainland and abroad.

"I think what director Yang Yu has done is taking an ancient property, something that every Chinese is intensely familiar with, to fiddle around with it for modern audiences," said Elizabeth Kerr, a Hong Kong-based film critic.

Speaking on RTHK's Trending China programme, she felt the film was a breath of fresh air as the same mythological legends are featured again and again.

"The best part about the Ne Zha film is that they're not 'A Journey to the West', they're not 'Monkey King', which I understand that it is beloved ... [But] there's so much more that you can choose from," she explained.

"This is a kind of strange territory for overseas viewers, for people who know nothing about any of the culture on this side of the world, it's going to be fresh to them."

The sequel to the 2019 hit Ne Zha smashed box office records on the mainland just two weeks after its release.

The film went on to dethrone Disney's "Inside Out 2" as the highest-grossing animated movie of all time.

Kerr believes the sequel's more sophisticated and refined visual effects attributed to its success.

But she struck a cautious tone over the film's release in the US market, saying it may not replicate the kind of success seen for Crouching Tiger, Hidden Dragon, the Oscar-winning martial arts epic in 2000.

"Partially because Crouching Tiger had a wider release. It also had considerable movie stars in it, and a powerhouse distributor pushing it," she said.

But she insisted Ne Zha 2's value should not be solely judged by its box office revenue.

"Ne Zha 2 is one of those things that is very much lightning in a bottle. People will try and repeat it. But you can't force it because how it happened was organic - no one will ever be able to tell you why this worked for this year, at this time, in this country, why it succeeded, no one can."

She also hoped Ne Zha's success will encourage mainland filmmakers to experiment with different varieties of scripts, and be willing to "roll the dice" more.