"Leadership matters in a crisis, and New Zealand's leader, Prime Minister Jacinda Ardern, can surely take considerable credit for this thus far hugely impressive outcome," he says.

"If you add the outcome of that single-figure death toll in New Zealand to the public performance of leadership, Ardern is surely one of, if not the, standout leaders of this crisis."

Campbell's praise came after a widely-read piece for the Washington Post by Kiwi journalist Anna Fifield, which highlighted Ardern's uncompromising approach to the alert level 4 lockdown, a four-week period of closures and self-isolation designed to flatten the curve of COVID-19 cases, and the swift shut down of the country's borders.

"From the earliest stages, Ardern and her team have spoken in simple language: Stay home. Don't have contact with anyone outside your household 'bubble'. Be kind. We're all in this together," Fifield wrote.

"She's usually done this from the podium of news conferences where she has discussed everything from the price of cauliflowers to wage subsidies. But she also regularly gives updates and answers questions on Facebook, including one done while sitting at home - possibly on her bed - in a sweatshirt."

Campbell also points to Ardern's press conferences, interviews and social media posts, calling them a "masterclass in crisis communications" in how she focused on the human - as well as economic - consequences of the lockdown.

"She set out, and explained in detail, but in clear, simple language, the four stages of Alert, and what each would require of government and of people. Her manner was calm, authoritative, and friendly," he writes for The Independent.

"Locked away at home for 23 hours a day, I spend many of those hours studying different world leaders as they deal with the COVID-19 challenge.

"Ardern is the only one who seems to be smiling as much in the crisis as she does in what might be termed normal times. It seems to help her, and New Zealand, get through it."