Thousands of disappointed gamers were unable to download the multiplayer, beta version of Halo 3 demo yesterday due to technical difficulties.

Xbox 360 gamers were instructed to download the code in a specially marked copy of the game "Crackdown" for the 360 but the option remained locked throughout yesterday.

The hotly anticipated Xbox 360 game is set to be a massive hit for Microsoft's gaming console, as were the previous versions for the previous consoles.

The two earlier games have sold more than 14.5 million units worldwide while logging more than 650 million hours of multiplayer action on Xbox Live.

Microsoft has not offered an explanation, but Bungie Software, the game's developers state on their website, "We realize this has been a pain for many and an inconvenience at the very least. Given the circumstances, we've decided to extend the duration of the Halo 3 Beta from June 6th to June 10th at 11:59 PM PDT. So, you lost almost a full day of play today but to make up for it we're tacking on four more days (and a weekend at that)".