Poverty Bay iwi Rongowhakaata on Wednesday buries its leader Darcy Ria, who died on Sunday.
Mr Ria, 89, served in C Company of the Maori Battalion, arriving in Italy towards the end of the Battle of Monte Cassino and going through to Trieste.
On his return he joined the Department of Maori Affairs and worked in the Gisborne office and the Maori Land Court until retirement, when he devoted himself to tribal affairs.
Rongowhakaata spokesperson Lewis Moeau says Mr Ria was also the source of much of the traditional evidence for environmental and Treaty claims, and for the tribe's challenge to the national museum.
Waatea News reports the funeral service begins at 11am at Manutuke marae.