Assuming you entered Thailand on a Non-O visa based on retirement, there is no way to my knowledge on how to convert this to a visa or extension of stay that allows a work permit.
IF I remember correctly, kiwis are slang for people from Australia. You can contact the Australia Chamber of Commerce in Thailand, and ask them if there are any special exceptions or treaties for people of your nationality. I'm sure someone would know:
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H/T to
@Kathy *******************
; Kiwis are people from New Zealand. They also have a chamber of commerce as well;
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They may be able to help you too.