Another two protesters have been arrested outside the New Zealand Defence Industry Association conference in Palmerston North.
The two men were arrested for disorderly behaviour after climbing on top of buses as part of a protest.
Police said the men were "arrested without incident, complied with police instructions and came down from the roofs willingly".
The two were released and given pre-charge warnings, police said.
Ten protesters were arrested yesterday, on the first day of the conference, for assaulting police, disorder and obstruction.