Dear Sophie,

I found a couple of TEWHATAs at the following website [just cut and paste into your browser]:-

http://www.manukaumemorialgardens.co.nz

Tewhata, John Thomas buried 1970 Manakau Memorial Gardens
Tewhata, Joyce Maureen Margaret buried 1995 Manakau Memorial Gardens

NOT SEARCHED:
Kapiti District Council
Gallipoli War Graves

And if you become a member of the New Zealand Genealogical Society I am 100% positive they will be able to assist with TEWHATA and NGAWHAU surnames.

At this link below, you can register your surname interests:-

http://books.dreambook.com/wlorac/surname.html

Also, sign up as a user of this site:-

http://www.maori.org.nz

and join their Whakapapa club.

Another good site is pearlspad:-

http://www.pearlspad.bravehost.com/index.html

Good luck ... Allycat in Australia.
PS My husband is of Maori ancestry.

I am a descendant of doug tewhata. My grand father was eru tewhata who had only 3 children, his wife was ripeka Kaihe. I have 11 siblings which include myself.