The US President on Wednesday said that the United States would bomb Iranian civil infrastructure every time Tehran fires at ships in the Hormuz Strait.
A Safe Travel advisory issued by Mfat said New Zealanders should leave Iran as soon as possible if it is safe to do so.
A limited number of flights are still operating from Khomeini International Airport in Tehran but airspace closures could occur at any time, it says.
Land routes out of Iran via Turkey and Armenia are still viable and have been successfully used by other New Zealanders to leave the country.
Anyone who cannot leave Iran should follow the advice of local authorities and move to or remain in a safe place and ensure they have essential supplies such as food, water, torches, batteries or power banks and any medications.
The advisory says there are a number of steps people should take if they are at risk of drone or missile attacks.
New Zealanders who need urgent consular assistance should contact the 24/7 consular emergency line on +64 99 20 20 20.