Locations of interest in the Tauranga area have been identified by the Ministry of Health after an Auckland truck driver tested positive for Covid-19.
Contact tracing has linked the driver to the existing Delta outbreak and the person has delivered supermarket supplies to Cambridge, Hamilton and Tauranga.
The locations are BP Tauriko in Tauranga on 11 September and Uppercrust Bakery in Mt Maunganui on 11 and 24 September.
The BP petrol station was closed for deep cleaning but has now reopened. A spokesperson said affected team members were isolating, undergoing testing and monitoring themselves for symptoms.
An Auckland location, the SuperValue in Flatbush, Clover Park, on 14 September was also added to the list.
Associate Minister of Health Minister Peeni Henare told Morning Report earlier he understood the driver had probably become infectious while outside Auckland.
"My understanding is it was while they were doing that trip, is the advice that I've been given from the health authorities.
"My understanding was that that individual had a Covid test during or close to and around the time those trips were being made."
He said health officials regarded the health risk as low.
"The data and the conversations I've had with health officials is that this isn't a hugely concerning case for us. We've managed to isolate this particular truck driver, we've isolated household contacts and all the work's been done to do the investigation.
"[The test] was done due to the surveillance testing measures that were put in place," he said. He understood it was carried out before the person knew they were a contact of someone who had Covid-19.
He did not know whether the driver was vaccinated.
The case highlights the need for surveillance testing for those who travel across the border, he said.
As of midnight, essential workers crossing the Auckland border need to provide proof they have been tested in the last seven days.
Mainfreight managing director Don Braid said arrangements with saliva testing were working well and 70 percent of the company's drivers were vaccinated.
Most of his drivers deliver freight to a single facility, and other vehicles move the goods out from there.
"Those line haul drivers who are crossing the border are really only going point-to-point.
"They are all now carrying vials for self testing and they'll do saliva testing ... twice within seven days with two days apart."
The Covid-positive driver is not a Mainfreight employee, he said.
The Ministry of Transport said so far 176 employers had registered for saliva testing covering 1824 workers. Another 351 permitted workers have registered as individuals.
Transporting New Zealand chief executive Nick Leggett said any frontline industry had a risk of workers inadvertently spreading Covid-19, but social distancing, hygiene and use of PPE on sites has prevented that. Testing was "the ambulance at the bottom of the cliff" and an array of preventative measures including vaccination were a priority.