Some Australians aren't laughing about Will Ferrell's latest movie Land of the Lost, the most complained-about film this year.

The Classification Board has received 19 complaints about Land of the Lost in the two weeks since its release.

Objectors argued that its sexual references and coarse language made its PG (parental guidance) rating inappropriate.

Herald Sun critic Leigh Paatsch pre-empted such concerns in his review of the film: Parents should ignore the inaccurate PG rating Australian censors have given Land of the Lost. This tripe will just rot the minds of children.

Also clocking up 19 complaints this year was the graphic novel adaptation Watchmen, released in March with an MA15+ rating. Some viewers objected to its violence, nudity and a particularly violent sex scene.

Another R18+ horror film, Seed, which went straight to DVD, received complaints about its graphic opening scene, which featured actual footage of animals being skinned alive. The footage was supplied by the animal rights activist group People for the Ethical Treatment of Animals.

Heist film The Bank Job, which starred British tough guy Jason Statham, received seven complaints about sex scenes and nudity. It was rated MA15+ and carried the advice that it contained strong coarse language and sexual references.

Complaints from the public have prompted the chief censor to lift the rating for the film Land of the Lost from PG to M.

Chief censor Bill Hastings said New Zealand automatically adopted G, PG and M ratings from Australia, but the system was not always perfect.

But there is an inbuilt safety valve - if members of the public are concerned about a film's rating they can ask me to review it.

The M label applies to films containing offensive language and sexual references.