Go to a resettled region down under (5)
I believe the answer is:
otago
'region down under' is the definition.
(I've seen this before)
'go to a resettled' is the wordplay.
'resettled' indicates anagramming the letters (letters must be resettled in a new order).
'go'+'to'+'a'='gotoa'
'gotoa' with letters rearranged gives 'OTAGO'.
(Other definitions for otago that I've seen before include "Old province" , "Region in South Island, New Zealand" , "NZ region round Dunedin" , "Part of South Island" , "Dunedin is its chief town" .)