Wainui was killed in a single-vehicle accident at McLaren Falls Park near Tauranga when his car hit a tree in the early hours of Monday.
As well as featuring 10 times for the All Blacks, he also made 44 appearances in Super Rugby for the Chiefs and broke the record for the number of tries in a single game in the competition with five against the Waratahs in June.
The former New Zealand Under-20s international joined Bay of Plenty in May for the 2021 National Provincial Championship campaign.
Chiefs and Maori All Blacks head coach Clayton McMillan led the tributes for Wainui, who also previously played for Taranaki and Crusaders in his homeland.
"He was an influential member in the teams he has been a part of and his presence will be missed," McMillan said.
"He epitomised everything you could possibly ask for in a player. He will be remembered for being a passionate, hard-working, proud Maori who was an exceptional player but more importantly father and husband."
New Zealand Rugby chief executive Mark Robinson added: "We know Sean's passing will be felt deeply by everyone involved in rugby, particularly his Bay of Plenty and Chiefs team-mates and we share their sorrow and their shock."
The Chiefs posted on Twitter: "One of Rugby NZ's tallest totara trees has fallen.
One of Rugby NZ’s tallest totara trees has fallen. To you Sean, our Rangatira, we farewell you to the outspread arms of the multitudes who await you beyond this earthly realm. You leave us here bereft and drown in sorrow as we weep for you. Rest well in peaceful repose. ❤️💛🖤 pic.twitter.com/ZhiCJ28OU1— Gallagher Chiefs (@ChiefsRugby) October 18, 2021
"To you Sean, our Rangatira, we farewell you to the outspread arms of the multitudes who await you beyond this earthly realm.
@ChiefsRugby and @BOPRugby would like to jointly express our sincere condolences and deep sorrow at the tragic passing of Sean Wainui ❤️— Gallagher Chiefs (@ChiefsRugby) October 18, 2021
JOINT STATEMENT 👉https://t.co/xpN04KEJVh pic.twitter.com/ng8QcWUqXN
"You leave us here bereft and drown in sorrow as we weep for you. Rest well in peaceful repose."
Wainui is is survived by his wife and their two children.