A horror film co-written by New Zealand based movie and television screenwriter Neil Cross took the top spot at the North American box office over the weekend.

Mama, co-written with Andres and Barbara Muscietti, earned $28.1 million from Friday through to Sunday at US and Canadian theatres, according to Universal Pictures estimates.

It is Cross' first film script, although he has others in the works.

The 100-minute film stars Jessica Chastain, Nikolaj Coster-Waldau and Megan Charpentier and tells the story of two young girls who, having been presumed dead, emerge from the woods five years later.

The film was executive produced by Academy Awards nominated director Guillermo del Toro.

Cross, who lives in Wellington, has written two episodes of the upcoming season of Doctor Who alongside showrunner Steven Moffat and Neil Gaiman. He is in line to write a New Zealand set episode after Sir Peter Jackson accepted an invitation to direct an episode from the show's lead Matt Smith issued in a Waikato Times interview.

Meanwhile, Jon Preddle, the Hamilton based author of the definitive guide to Doctor Who called Timelink, is seeking an Arabic speaking fan to translate some recently uncovered episodes from the show's early days dubbed into Arabic back into English.

Preddle is particularly interested in the Arabic dialogue which appears over the opening and closing credits of the 1964 William Hartnell serial Planet of Giants.

The fourth part of the story is one of 106 episodes from the show's first four years that are missing from the back catalogue because the BBC wiped them to reuse the tapes.

"The first three episodes of Planet of Giants have got the Arabic sound track on them and I have tried to find out through software what is being said," Preddle said.

The software had proved unreliable thanks to the music in the background.

Preddle had asked around Hamilton but so far found no-one able to help.

Anyone who can help can email: chris.gardner@waikatotimes.co.nz.