The small Waikato community where new cases of Covid-19 have emerged has been told to isolate and get a Covid-19 test, the deputy prime minister says.
Three people in one family in Whakatīwai have tested positive for Covid-19 after it was found a member of their household tested positive when on remand in Auckland's Mount Eden prison.
Deputy Prime Minister Grant Robertson told Morning Report officials have advised the town to get tested but Cabinet will wait to see what advice it gets before deciding whether to move the region into a higher alert level.
Currently the Waikato is in alert level 2.
"Both alert level 3 and level 4 have significant restrictions in terms of movement. Level 2 also has restrictions around distancing and mask wearing and so on."
Roberston says there's no indication the case emerged from the Waikato and preliminary indications show there may be an epidemiological link to one of the current clusters.
"It is more likely it was taken there and we're working our way through the contacts that this person has with potentially other clusters that we're still working on."
The person on remand at Mount Eden prison was bailed to a Waikato address on 8 September.
"We know from the GPS monitoring, because they were on bail, that they stayed at the address through until the 16th of September."
On 16 September the person appeared in court and was taken to Mt Eden for remand. It was on transfer that they were tested for Covid-19 - standard practice for Corrections.
It is within the Court's power to bail someone to an address outside of the alert level 4 area, Robertson said.
The family of the person - two children and an adult - have since tested positive.
There are nine people in the household, he said. There is one result outstanding and five household members have tested negative.
Robertson says one of the children may have been symptomatic at school late last week and those school contacts have been asked to isolate and get a test.
There is a pop-up testing station at the marae in Whakatīwai for others to be tested, he said.
"Obviously anyone in the wider area should consider isolating and get a test."
Robertson says all 20 cases from Saturday have been linked to the current outbreak.
"What that indicates, as officials have said over the last few days, we don't believe we have widespread community transmission. What we have is a series of clusters where because Delta is what it is - and when it gets into a household many people get infected - we're going to see a reasonable number of cases.
"What we're particularly focused on is whether or not we see cases that emerge which would mean that we didn't have the outbreak under control."
With Delta, the numbers are only one factor in decision-making, he said.
"An important factor is whether we have uncontrolled transmission or transmission outside households."