It depends on whether you’re talking about OOB or Alpha. In OOB, kamikaze may be used if the ships end their combat movement in a kamikaze zone, whether or not there is a battle. In Alpha, kamikaze are triggered by combat, not combat movement, so the ships must actually fight in a kamikaze zone (or launch an amphibious assault from it) in order to be targeted.
MOVED: Neutral Powers rules
This topic has been moved to House Rules.