Covid-19 Response Minister Chris Hipkins says contact tracing shows the two new community cases did come from the daughter in the Case A family.
Hipkins told RNZ's Checkpoint that after the high amount of testing and contact tracing over the past three days they were satisfied the risk of community spread was low.
"We're not completely out of the woods yet, we're going to level two, we're not going all the way down to level one, but we are confident that around the rest of the country, New Zealand can return to level one and in Auckland we've still got a little bit more work to do."
If there are more infections among known contacts of existing cases there is no cause for alarm, Hipkins says.
"If we're seeing new cases that are not connected to our existing cases, that's something we'll consider differently."
Despite saying there may still be new community cases linked to the cluster, he was "very confident" in the decision to move down alert levels.
Auckland and wider New Zealand will drop one level each - to levels 2 and 1 respectively - from midnight tonight.
"I'm certainly not going to say there won't be more cases out of this cluster but as long as they are connected to the cluster and our contact tracing system is identifying them, then we can manage that without the need for alert level escalation," Hipkins said.
In making the decision to move alert levels, the government had wanted to make sure it had eliminated the risk of undetected community transmission.
"We've done a good wave of testing, of contact tracing around these cases to identify whether or not there was undetected community transmission. We're now satisfied the risk of that is low...
"There's an important distinction to make here because it relates to the alert level. We're now treating these three new cases the same as we would have done if we had not already been at alert level 3 and alert level 2 for the rest of the country.
"So we're relying on our alert level system to isolate their close contacts, to do the testing, to stamp out the virus that way.
"The alert level escalation is for where there could be undetected community transmission."
University of Auckland professor Des Gorman said he felt unease with the decision to lower the alert levels.
"I think the reason I share that unease is because the level of risk we seem to be tolerating is going up and down almost imperturbably," he told Checkpoint.
"For example, the Ministry of Health found out about these cases on Saturday night but didn't think it was necessary to tell the prime minister for 12 hours. So things which should have been cancelled if we needed to be in alert level 3... weren't.
"I can't see a consistency in our risk appetite, it seems to go up and down depending upon the optics of the situation."
The most reassuring thing was the absence of virus particles in wastewater test results, he said.
The new cases were more recent than the other cases identified in the cluster, Hipkins said.
Testing showed they had "only recently been infected and that they have been incubating the virus for a shorter period of time".
Asked about the new case who worked at a McDonald's restaurant in South Auckland, Hipkins said: "My understanding around the time period in question here is the risk is still quite low".
The source of the community transmission that led to the cluster is still unknown.