It's essential for the whole of Auckland to go to alert level 3 according to one epidemiologist.
Auckland went to level 3 this morning, while the rest of the country went to level 2.
Otago University epidemiologist Micheal Baker told The Weekend Collective it's important to prevent the spread of the virus no matter where in the country you are.
He says that while it wasn't impossible to have small scale borders within Auckland, it wasn't safe enough.
"The trouble is we know that the people move a huge amount across Auckland. There will be people who live in the northern half of the city who cross the Harbour Bridge every day and work in South Auckland, and vice-versa."
The lockdown was also deemed necessary as the case announced last night - Case M - was a 21-year-old man who had not been self-isolating, including going to a gym after getting his Covid test.
However, Baker says that punishment is not the best way to go about making people follow rules.
"I think the law is very strong if it's needed, but the hope always is to promote voluntary behaviour."