He said he felt extremely sad about what had happened, especially in a peaceful country like New Zealand.
The team felt stronger than ever in its campaign for peace and he said now was the time to urge politicians to make changes, specifically in disarmament.
From London, Paris, and India, all the way to New Zealand, the team has met, and will meet, several prominent leaders during the expedition.
Alyn Ware, a former Tauranga local who joined the team, said he was shocked by the horrific and senseless violence that occurred last week.
It devastated him that a person could be filled with so much hate, but also be so dehumanised to do something of that nature, he said.
Both Naerland and Ware said the New Zealand response to the tragedy has been inspirational.
Naerland said it was clear that "at all levels, every one of us can act for peace".
After laying flowers and paying their respects, members of the team were off to meet mayor Gary Brownless, who is a member of the "mayors for peace" group.
The rest of the team's trip in the city consisted of doing a presentation at Our Place in the CBD, before heading to Otumoetai College.
Naerland said he was particularly looking forward to chatting with the college students, because young people are the future so it's important to get through to them.
Naerland was awarded the Gandhi Foundation International Peace Award in 2015 and the Norwegian King's medal of honour in 2017.
During the peace trip, the team is to meet with the president of the United Nations to discuss nuclear disarmament, climate protection, and prevention of hate violence, among other things.
The team will head to Auckland tomorrow before flying out to complete the Hawaiian leg of the trip.