Manhunt 2 has been hacked just 24 hours after going on sale to show violent scenes that were blocked by the censors.

The game had certain scenes removed in order to gain certification in the US. Manhunt 2 has still been deemed too violent for release in the UK, although it may be available online to get around regulations.

Take2 Interactive, the game's distributor, decided to block the offending scenes from the game player's view rather than remove them completely. Inevitably, a hack is now in circulation to make some of the scenes visible.

"I stand behind the game and the Entertainment Software Rating Board process," said Take2 Interactive chairman Strauss Zelnick in a statement.

"It is unfortunately the case that no one in the entertainment software industry is immune from hacking. We hope that consumers will not engage in hacking or download illegally modified copies of our games."

The hack has appeared only for Sony's PlayStation Portable so far, and has yet to surface for the PlayStation 2 or Nintendo's Wii. Viewing the scenes requires a hacked console and a considerable amount of skill.

The incident mirrors that of Grand Theft Auto: San Andreas, which was developed by the same team. A hack allowed softcore pornography to be added to the gameplay.

Manhunt 2 has prompted outrage from consumer groups, which claim that it is too violent for general release.

"This game is absolutely inappropriate for kids," said James Steyer, chief executive at Common Sense Media.

"Studies suggest that a large number of underage kids play M-rated games. Given the extremely graphic content in Manhunt 2, we want parents to know that even older teens are not ready for this title."