Harris is one of four new caps in the 26-strong group, along with Chiefs team-mate Alex Nankivell, Hurricanes first-five Fletcher Smith and Highlanders outside back Jordan Hyland.
Harris and Tahuriorangi are two of six players with All Blacks experience, with Highlanders' Tyrel Lomax and Elliot Dixon, Blues number eight Akira Ioane and Crusaders halfback Bryn Hall also selected.
Māori All Blacks coach Clayton McMillan says it is a really exciting squad to name.
"I think we have a good balance between the experience of guys who know how to perform at this level, and those who bring an important fresh perspective and energy," McMillan said.
"We also have some returning after an absence and they will bring some important knowledge into our group."
McMillan plans to name a 27th player, likely to be a prop before the squad travels to Suva next week.
"Pulling on the Maori All Blacks jersey is a wonderful opportunity, and I know that these players will want to represent their heritage, their whanau and their country well.
"These next two fixtures will allow players to showcase what they have, and really put their best foot forward for higher honours.
The Maori All Blacks are relishing the chance to play a side in the midst of preparations for the Rugby World Cup.
"For some time we've been coveting a strong international opposition, and Fiji certainly fits that bill," McMillan said.
"I'm very excited about coaching a Maori team that is playing in Rotorua - what we consider to be the sentimental home of the Māori All Blacks."
The Māori All Blacks full squad is (with Iwi, Province, Super Rugby Club):
Ash Dixon (Ngati Tahinga) Hawke's Bay/Highlanders
Nathan Harris (Ngati Apakura/Tainui) Waikato/Chiefs
Tyrel Lomax (Ngai Tuhoe/Muaupoko) Tasman/Highlanders
Ben May (Ngati Maniapoto) Hawke's Bay/Hurricanes
Marcel Renata (Ngati Whanaunga/Ngai Takoto) Auckland/Blues
Ross Wright (Ngati Whatua/Ngati Porou) Northland/Blues
Tom Franklin (Ngati Maniapoto) Otago/Highlanders
Pari Pari Parkinson (Te Whanau a Apanui) Tasman/Highlanders
Isaia Walker-Leawere (Ngati Porou) Hawkes Bay/Hurricanes
Whetukamokamo Douglas (Ngati Porou/Ngati Whakaue) Canterbury/Crusaders
Elliot Dixon (Ngapuhi) Southland/Highlanders
Akira Ioane (Ngapuhi/Te Whanau a Apanui) Auckland/Blues
Mitchell Karpik (Rongomaiwahine/Ngati Kahungunu) Bay of Plenty/Chiefs
Reed Prinsep (Te Rarawa) Canterbury/Hurricanes
Bryn Hall (Ngati Ranginui) North Harbour/Crusaders
Jonathan Ruru (Ngati Kahungunu/Rongomaiwahine) Auckland/Blues
Te Toiroa Tahuriorangi (Ngati Pikiao) Taranaki/Chiefs
Otere Black (Ngai Tuhoe/Te Whanau a Apanui/Ngati Tuwharetoa) Manawatu/Blues
Jackson Garden-Bachop (Ngati Awa) Wellington/Hurricanes
Fletcher Smith (Ngati Kahungunu) Waikato/Hurricanes
Alex Nankivell (Ngapuhi) Tasman/Chiefs
Rob Thompson (Ngati Kahungunu/Nga Rauru) Manawatu/Highlanders
Teihorangi Walden (Te Atiawa) Taranaki/Highlanders
Jordan Hyland (Ngai Tahu) Northland/Highlanders
Shaun Stevenson (Ngapuhi) North Harbour/Chiefs
Sean Wainui (Ngai Tuhoe/Ngati Porou) Taranaki/Chiefs