The Powers of Attorney Act governs the making of powers of attorney in the Territory. The Act allows for two types of power of attorney (POA) - a springing POA and an enduring POA. A springing POA becomes effective either on a specified date or upon the occurrence of a specified event (such as if you become incapacitated). An enduring POA becomes effective as soon as it is signed and continues in effect until you revoke it or until your death.
NWT law does not require you to register your power of attorney anywhere, but you should make sure that the person you appointed as your attorney has a copy. Also give a copy to any person or firm (such as your bank) which may need to rely on it.