Heading north, wander with one New Zealander (5)
I believe the answer is:
maori
'new zealander' is the definition.
(the Maori are indigenous people of New Zealand)
'heading north wander with one' is the wordplay.
'heading north' is a reversal indicator (in a down clue, letters travel north).
'wander' becomes 'roam' (synonyms).
'with' means one lot of letters go next to another.
'one' becomes 'i' (Roman numeral).
'roam' written backwards gives 'maor'.
'maor'+'i'='MAORI'
(Other definitions for maori that I've seen before include "Pa may accommodate one" , "Native language of NZ" , "Native New Zealander of Polynesian origin" , "One of New Zealand's aboriginal people" , "Native of Aotearoa" .)