Police yesterday had to turn away a number of vehicles at Auckland's borders with people who were trying to visit friends or to get to a holiday home.
Every vehicle that comes in and out of the city is being checked after Auckland went into Covid-19 alert level 3 lockdown yesterday.
"We need to validate that people have a reason for passing through on either direction, there's permission to pass through Auckland if you need to in order to get home for instance," Police Commissioner Andrew Coster told Morning Report.
Coster said police have been "comfortable" with compliance at the moment, and most people have also been patient and understanding.
"The officers [at the checkpoints] will assess the situation against the rules but we have to be pretty careful clearly that we don't allow people to just come through if they don't meet the requirements.
"There's judgment that needs to be exercised ... we have pretty firm controls in place. Obviously we need to keep freight moving and we have to make sure that the supplies Auckland needs get through.
"Most people are coming through with some kind of evidence that they have a reason to pass."
He said they had enough staff to monitor the nine checkpoints.
"The challenge is keeping traffic flowing smoothly with the required level of checks and that's a balancing act but we're managing that well."