NZ native, upstanding character, wanders up (5)
I believe the answer is:
maori
'nz native' is the definition.
(I've seen this before)
'upstanding character wanders up' is the wordplay.
'upstanding character' becomes 'I' (vertical or upright letter or character).
'wanders' becomes 'roam' (I am not sure about this - if you are sure you should believe this answer much more).
'up' is a reversal indicator (in down clue: letters go upwards).
'i'+'roam'='iroam'
'iroam' reversed gives 'MAORI'.
Can you help me to learn more?
(Other definitions for maori that I've seen before include "I roam (anag)" , "Member of New Zealand's aboriginal people" , "antipodean language" , "Native of New Zealand and the Cook Islands" , "native people" .)