Technology to detect SARS-CoV-2 viral fragments in wastewater was improving internationally, including in New Zealand and at the University of Otago, Prof Neil Gemmell said.
Prof Gemmell’s university research group had already detected coronavirus in wastewater at Dunedin’s Tahuna Wastewater Treatment Plant in March-April of last year, he said.
Wastewater testing has recently been used in Auckland as a further, wider check for coronavirus after the recent community outbreak involving a father, mother and daughter.
A geneticist, Prof Gemmell is part of a national group, led by the Institute of Environmental Science and Research Limited (ESR).
He said ESR had already conducted significant research over wastewater detection, but some people argued that New Zealand was already controlling Covid-19 and strengthening wastewater detection was unnecessary.
He strongly disagreed.
"Obviously, our situation in New Zealand is very privileged," compared with many other people overseas, he said.
However, circumstances could change "very fast", he warned.
"We can’t take that freedom for granted."
"The question we have to ask ourselves is what are we prepared to do to keep ourselves in that privileged position," he said.
Vaccination would make a big difference, but New Zealand had to protect itself long term against a virus still capable of killing some people each year.
Major advances in genomic testing of coronavirus had taken place in New Zealand last year, all positive cases now being sequenced and the value of doing so more widely understood.
He urged similar advances in wastewater testing, particularly pumping in more Government resources to greatly speed up test results, and provide national coverage, including monitoring of airports and MIQ facilities.
"Managing Covid is all about information," he said.
Late last year, ESR undertook an eight-week pilot testing programme involving many areas, including Dunedin, Invercargill and Queenstown.