A Kiwi scientist and expert on saliva-testing is questioning the advice given to Prime Minister Jacinda Ardern, which has had her coming off as misinformed and "fumbling over saliva testing".
Dr Anne Wyllie, a research scientist at the Yale School of Public Health, was so concerned about the state of saliva-testing in New Zealand that she wrote to the Ministry of Health and Ardern last month.
But her criticisms of Asia Pacific Healthcare Group - which holds the ministry contract for saliva testing - have been called "unfounded and not based on fact", according to APHG's consultant clinical microbiologist and Otago University Associate Professor James Ussher.
And a spokesman for Ardern referred to the Prime Minister's earlier comments about relying on the public health advice she receives.
Saliva testing can be a reliable alternative to the more invasive nasopharyngeal test, but despite repeated recommendations to the ministry to use it over the past 12 months, it remains infrequently used.
Wyllie has been at the forefront of saliva testing technology, having pioneered with her team the SalivaDirect test, which attracted global attention last year.
In her letter, she said APHG was using testing methods that weren't diagnostically validated - a claim APHG has rejected.
She outlined further concerns over saliva samples being collected in an unsupervised manner, and over test results from ESR that "have not performed to a level that would be considered acceptable in the United States and other countries for public use".
She told the Herald she remained concerned about the quality of advice given to Ardern, saying she appears to be misinformed.
Asked to clarify, Wyllie pointed to remarks Ardern made on August 26 about saliva testing taking just as long to process as nasopharyngeal swabs.
Ardern had said: "If [the saliva test] is PCR-based, it takes as long to process it as a nasal swab. There are other forms of testing that are rapid, but they don't have quite the same level of accuracy as the saliva testing that you process as PCR. There are other forms of testing that are rapid, but they don't have quite the same level of accuracy as the saliva testing that you process as PCR."
But Wyllie said the method used in SalivaDirect could return a result in about six hours, while Rako Science, a provider that has been servicing private sector including healthcare providers, says its process takes just over three hours.
Wyllie said Ardern's comments showed "fumbling over saliva testing".
"It's unclear what she means regarding rapid testing in this context, and [she's] perhaps casting doubt over faster saliva-based PCR methods on offer."
Sir Brian Roche, in his review of the February cluster, told the Minstry of Health that there needed to a stronger role for independent science advice.
Wyllie told the Herald that APHG was using a number of different methods, "none of which are really being used by other countries around the world".
"This is ridiculous when they should be working with labs to replicate the methods that have already been proven to be robust and used in testing programmes overseas."
But Ussher said APHG's testing had been diagnostically validated - though it had been harder to collect samples, given how little Covid has been in the country - and accredited by International Accreditation NZ against the appropriate international standard.
The use of different methods provided "resilience", he said.
"All those assays have been assessed and have been shown to be as good as or superior to the extraction-free methods such as SalivaDirect.
"We have a large amount of experience in the diagnostic pathology space, and a team of nine microbiologists and many very experienced medical laboratory scientists."
Covid-19 Response Minister Chris Hipkins has said repeatedly he has wanted saliva testing in place much sooner.
On Wednesday he said during Question Time that saliva testing was meant to be available for border and MIQ workers towards the beginning of August, but so far only 863 workers had signed up.
"The indications I had back in July were that it would be in place for all those on a seven-day testing cycle towards the beginning of August. Clearly, that has not happened, and I'm disappointed that that has not happened."
A spokesperson for the ministry said saliva testing will become an option for more groups over time, including healthcare workers and returnees in MIQ facilities.
The ministry was exploring options for providers other that APHG.
"We are in the process of finalising a contract with a saliva testing provider, and expect saliva testing as an option for workers who need weekly testing so they can cross the Auckland boundary will be available by then."