Japanese director Kinji Fukasaku is preparing a director's cut of his controversial gore fest, Battle Royale, which should enable its target audience of under 16-year-olds to see the film for the first time in Japan.

The dark, futuristic thriller, about a group of 15-year-olds on a desert island who are picked off one by one, has not only been lambasted by members of the Japanese Parliament and the minister of education for its ultra-violence, but slapped with an R-15 rating by the censors.

Unsurprisingly, the controversy hasn't hurt the film's box office which has soared to $20.9m (Y2.4bn) on 1.8 million admissions since its release on December 16.

Fukasaku plans to spend a week filming new scenes and add others left on the cutting room floor for his director's cut, which producer-distributor Toei will release in theatres on April 7.

Producer Kenta Fukasaku, the director's 19-year-old son, said the reason for this unprecedented post-release shoot is to "add scenes that deepen the portrayal of the individual characters," nearly forty of which get bumped off with gun blasts and explosions during the course of the film. However, such a move is likely to win the film a lower certificate which could propel its domestic box office even further. It could also help the film's international prospects. Battle Royale stirred up a large amount of distributor interest at last week's Rotterdam International Film Festival, and has already been sold to the UK's Metro Tartan.