iPhone unable to send texts to New Zealand after moving to Australia

Have updated to latest IOS, resetting and restarting but has not helped. Can send iMessages but not texts internationally. Have recently moved from New Zealand to Australia and am unable to send text messages to NZ. Have tried texting from an android phone and that works so it is not my provider or sim card. It seems to be an issue with my phone.

[Re-Titled by Moderator]