Halliday said he planned to invite Prince Harry to attend the commemorations, given his role in the armed forces, so he could honour the long-lost graves of British soldiers rediscovered in 2017.
''We may not get him but you have to aim for the skies,'' he said.
He also wanted to see a visitor centre and a museum to display the taonga currently stored at Whangārei Museum.
''The last battle here in the North shaped the country as it is today, whether you like it or not,'' Halliday said.
The trees have been provided by Matariki Tu Rākau, which is part of the Billion Trees Programme and aims to plant 350,000 trees around the country as living memorials to New Zealanders who died in conflicts overseas and on home soil.
Most of the planting work so far at Ruapekapeka — 20,000 trees this year and another 10,000 planned in 2020 — has been done by offenders sentenced to community work.
Since the beginning of July up to 24 community workers and four supervisors a day have been on site five days a week.
To celebrate progress so far a ceremony was held on Friday when a plaque was unveiled and trees planted by students from Moerewa and Whangārei Intermediate schools.
DOC works officer Shaughan Anderson, of Whangārei, praised the co-operation that had made the project possible, saying ''you can't do good conservation without working together''.
''We had a desire to plant the area but couldn't find the plants or the labour. DOC can't do this job alone.''
Species planted include kanuka, karamu, mahoe, cabbage trees, flax and kahikatea.
The Battle of Ruapekapeka Pā (December 1845-January 1846) was the last engagement of the Northern War between Maori, led by chiefs such as Te Ruki Kawiti and Hone Heke, and British forces and their Māori allies.
The pā, which is about 20km southeast of Kawakawa, is considered the pinnacle of 19th century Māori military architecture and was recognised in 2008 as a national site of engineering significance by the Institute of Professional Engineers of New Zealand. The British were said to have applied the lessons they learnt from Ruapekapeka in the Crimean War and World War I.
■ The International Visitor Conservation and Tourism Levy (IVL) is investing $1.2 million into making Ruapekapeka Pā a bigger drawcard for tourists.
The money, from an $18m pool IVL is giving out to 10 tourism projects this year, is designed to help make Ruapekapeka Pā a drawcard for visitors, functioning as a hub connecting other Land Wars sites in the region.