The local Southern Skinheads gang had threatened to attack Hells Angels members if they turned out for the Poker Run ride from Nelson to Tapawera and back.

Quote from the article:

The Southern Skinheads reportedly believed the Hells Angels would bring drugs with them, including P. The Skinheads had allegedly threatened to fire shots and burn down bars and clubs. Nelson Mayor Kerry Marshall said he was confident police were on top of the situation and a police operation was put in place to deal with any possible violence.

Source: Skinheads threaten Hells Angels