A Ministry of Health spokesperson said ESR had arranged for further samples to be collected from Tauranga and Mount Maunganui to provide "further confidence" that it was unlikely there were undetected Covid-19 cases in the community.
Results were expected "over the coming days".
The ministry urged anyone anywhere in the country with cold or flu symptoms to call Healthline for advice on getting a Covid-19 test.
In the 1pm briefing on Tuesday, director-general of health Dr Ashley Bloomfield said a wastewater sample taken on September 23 in Tauranga had tested positive.
Four hundred people were tested in the Tauranga area after the positive result. Bloomfield urged Tauranga residents and those in the wider motu to get vaccinated.
Tauranga MP Simon Bridges told the Bay of Plenty Times the five days it took to inform people of the positive result seemed "too long", however a Ministry of Health spokesperson said it was "incorrect" to say it took five days.
The ministry received regular reports from ESR with results of its wastewater testing, the spokesperson said.
"While the sample was received on Friday, the detection in Tauranga was included in ESR's report, which [was] received on Monday evening.
Fifth Avenue Medical Centre GP Dr Luke Bradford. Photo / George Novak
"The result was reported within two working days of the sample being received by ESR. This included time for repeat analysis of the samples due to the low levels of the virus initially detected."
The spokesperson said unexpected wastewater results could be from a recovered case who was "excreting viral fragments", or an undetected acute case.
ESR scientists worked "around the clock" to provide wastewater and PCR testing results in an accurate and timely way, while also continuing to provide laboratory services for other test results, the spokesperson said.
The Ministry of Health was asked how many people were released from a quarantine facility and travelled to Tauranga between September 9 and 23.
A spokesperson said "nothing in the data" indicated that anyone left MIQ and went to Tauranga during that time.
Fifth Avenue Medical Centre GP Dr Luke Bradford said yesterday there had "definitely been an increased demand" for testing after the announcement.
"Most of the clinics put on extra capacity," he said.
"We certainly did at Fifth Avenue, and we slowly filled that capacity throughout the day, but it's nowhere near the demand we were seeing at the start of the Delta outbreak."
Second Ave Accident and HealthCare manager Dave Gilbert said he had not noticed "any major increases" in testing.
"It's still been busy but it certainly hasn't increased dramatically."
The Bay of Plenty District Health Board's Covid-19 incident controller Trevor Richardson said additional testing capacity had been made available at GP practices in the greater Tauranga area.
"At present, there has not been any significant increase in testing demand. GP practices will extend testing hours, depending on demand."
