Sense Partners economist John Ballingall told RNZ the move could spark a potential retaliatory trade war between the nations, spelling bad news for New Zealand exports.
"The larger concern for New Zealand is that Trump's actions here lead to retaliation, which we're already seeing from Canada, Mexico and China, and that that blows up into a full-blown trade war.
"When that happens, you'll see global GDP growth go down, and that means lower demand for all of the things that New Zealand exports."
He acknowledged there are possible upsides in the short term. As dairy products going into Canada become more expensive. This could potentially open up new opportunities for New Zealand.
"I don't want to paint this as something which is great for New Zealand. The medium-term and longer-term consequences are pretty worrying."
Especially, he said, if the scope of Trump's tariff tactics widens to include Europe.
"Europe's already talking about how it might retaliate. We know the EU does this pretty effectively. It's got a list of products that it would counter-punch with.
"So again, it's not hard to see this skill heading relatively quickly into something much more concerning to New Zealand."
But while the actions of the US President have incensed those who believe the measures violate the rules-based system of fair trade, New Zealand is unlikely is join the choir.
"I think, to date, we've been very measured in terms of any political statements around President Trump's actions.
"I think that is probably going to be the way that we continue to go. There isn't a huge amount to be gained by jumping up and down and criticizing the US.
"Now that may sound like we're being a bit weak, but I think we have to be pragmatic. New Zealand making a song and dance isn't going to change President Trump's mind about tariffs, so perhaps we're better off taking the diplomatic route, trying to talk to people in this administration, position New Zealand as a partner."
Trump should be told 'allies are not lackeys'
But, Otago University international relations professor Robert Patman says New Zealand and other liberal democracies should make their opposition to the tariffs loud and clear.
"We always see ourselves as a good international citizen. Well, we actually need to walk the talk," he said.
"And that means to say we need to make it quite clear, along with Australia and other liberal democracies that Mr Trump's attempts to single out traditional allies of the United States for this sort of top-down pressure is unacceptable. Allies are not lackeys," he said.
Patman said Trump's "America First" approach to alliances and international institutions implies that other parties involved in the alliances took second place.
"I do think it is important that the United States is left under no illusions that everyone is going to quake in their boots and fold in front of them under Mr Trump."
Noting that New Zealand did have an ongoing trade dispute with Canada over dairy quotas under the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP), he said the relationship was strong.
