For Tandy, the experience was a culmination of an "amazing journey".
In May, last year, Tandy received a letter from the Australian Army which tasked him with collecting the samples from 100 battlefields, already identified by an Australian historian. From there, Tandy dealt with the New Zealand Government, the New Zealand Culture and Heritage Committee, Maori King Tuheitia and local iwi, resulting in yesterday's formalities.
"It has been a bit like an onion, just so many layers," Tandy said.
"It has been really interesting. I've even met a number of people, including Australians who didn't realise our troops came over here."
A total of 450 Australian soldiers were deployed to fight the wars in Tauranga. For some, the battles were their first.
Constitutionally New Zealand began as an extension of the colony of New South Wales, which was its status when the Treaty of Waitangi was signed in 1840. New Zealand became a separate colony in 1841 but was still linked to New South Wales, which had not yet joined the Federation of Australia.
The Battle of Gate Pa and the Battle of Te Ranga both happened in 1864.
"Just getting to this point, it has been a thought-provoking but also a very interesting and respectful journey really. It has been incredible," Tandy said.
The Anzac Memorial Centenary Project is being built in Sydney and expected to open later this year.
Ngai te Rangi kaumatua Puhoirake Ihaka said the soil collection was a positive and poignant moment.
"It helps to mend the hurt and to bring us closer together in today's world," Ihaka said.
In a letter from the director of the Office of Veterans Affairs, NSW, Caroline Mackaness said the memorial did not seek to glorify war but to use the common experiences of loss and grief "of all people's involved in conflict as a basis for empathy, understanding and a way to remember our joined history, honour each countries [sic] heroes and to heal our spirits".
The Battle of Gate Pa
The Tauranga Campaign was a six-month armed conflict in New Zealand's Bay of Plenty in early 1864. It was part of the New Zealand wars that were fought over issues of land ownership and sovereignty. British forces suffered a humiliating defeat in the Battle of Gate Pā (Pukehinahina) on April 29, 1864, with 31 killed and 80 wounded despite vastly outnumbering their Māori foe. They saved face seven weeks later by routing their enemy at the Battle of Te Ranga, in which more than 80 Māori were killed or fatally wounded, including their commander, Rawiri Puhirake.
The Battle of Te Ranga
Te Ranga was the sequel to the battle of Gate Pā. Following their humiliating defeat, some of the British force at Tauranga returned to Auckland. Meanwhile, their Ngāi Te Rangi opponents were reinforced by warriors from Ngāti Rangiwewehi, Ngāti Pikiao and Ngāti Porou. They began building a pā at Te Ranga, 5km inland from Gate Pā.