However, the men were spotted by a member of a nearby dojo.
Nathan Smith told his sensei and the rest of the students at Ninja Senshi Ryu and they rushed out to confront the thugs - all dressed in traditional black ninja garb.
On seeing the ninjas, the men fled, only to be later arrested by police.
"You should have seen their faces when they saw us in ninja gear coming towards them," the school's sensei, Kaylan Soto, told the Herald.
They also failed to notice a ninja, Nathan Smith, standing in the shadows outside the dojo. Mr Smith immediately alerted his sensei, or teacher.