Police have already set up roadblocks at the Auckland region "border" - eight are in place today.
She said border enforcement won't be conducting "evidence checks" for the first 24 hours to give people time to get their information in order.
"Basically, what we want everybody to do is stay home," she said. "We are asking people from Auckland not to leave."
But there are some exceptions. She said anyone who got an exemption last time can anticipate getting one this time.
That includes people who live on the "border" of Auckland and need to come into the region for legitimate reasons.
People can transit through Auckland if they are travelling from, for example, Hamilton to Northland, she said.
"We just ask you to remember that Auckland is in level 3 when you're passing through.
"But as much as you can, if you can postpone coming into Auckland even for work reasons that are legitimate, we'd really be pleased if you did that and just stayed put as much as you can."
She also again addressed the question of why the Government was allowing New Zealanders overseas to come home.
"Essentially we can't say to New Zealand citizens that they can't come home. If we did that we would potentially leave them without a home country that they are legally able to enter. You'll find no country in the world is barring its citizens… from coming home."
On the topic of testing, she urged everyone who was at one of the locations of interest during the relevant time periods to call Healthline and get a test.
"If you have not been during those times to those places of interest and you also aren't sick, no need to go out and get a Covid test."
She was asked about the rationale for why the rest of the country is staying at Level 2.
"That's essentially because we are in a position at the moment where we haven't quite identified… whether or not the household cases we've picked up, whether or not there are any beyond that. We're also very mindful that some of the period of time we're looking at have been over periods of long weekends where a lot of people have been moving around.
"It's essentially up to us to just make sure we are taking a precautionary approach given how much travel there has been and that we haven't quite put a ring around this case just yet."
She said domestic flights would continue to get people back home to where they need to be but that passengers may be asked about their reason for travelling.
