The Government has quietly opened the door for saliva testing to be used for the regular testing of border workers.
If used, it could counter workers' reluctance to get tested because it is much less discomforting than a nasopharyngeal swab.
It comes as the integrity of the testing regime for MIQ workers has come under intense scrutiny, following revelations that a security guard wasn't tested for five months.
Covid-19 Response Minister Chris Hipkins admitted yesterday that there may be up to 60 MIQ workers who aren't being regularly tested, though he insisted that the risk was "very low".
He has signed a new public health order which increases the frequency of testing for certain border workers, and requiring all companies with MIQ workers to use the Government's border testing register.
The order also enables, from April 21, the taking of saliva for the workers' tests in a manner approved by director-general of health Dr Ashley Bloomfield. Currently the testing has to be either a mouth or a nose swab.
The wider use of saliva testing has been pushed for by Otago University public health experts, and epidemiologist Professor Michael Baker welcomed the move.
Hipkins has also previously talked about how saliva tests were less invasive than nasopharyngeal swabs.
Yesterday Bloomfield told Parliament's health select committee about a study in Melbourne where 15 per cent of saliva swabs could not be used - but that was mainly because of the way it is collected and processed.
"Saliva testing, if it's validated, can be as sensitive as nasopharyngeal - remembering that both are PCR-based tests," Bloomfield told the committee.
"The issue is that there is a different and somewhat more complex process in collecting and processing a saliva sample."
Act leader David Seymour, who has also been pushing for wider use of saliva testing, shared people's poor experiences with nasopharyngeal swabs with Bloomfield.
"I've had reports of people who've had 100 nasopharyngeal swabs, people whose sinuses are actually collapsing and people bleeding. And of course people are going to be reluctant to get tested as a result."
The Ministry of Health has put out requests for proposals for contractors to do saliva testing "to complement ongoing nasopharyngeal", Bloomfield said.
The group most affected by invasive swabbing was international aircrew, he said, who were often tested after arriving and before leaving a country.
Air NZ's chief medical officer Dr Ben Johnston said saliva testing would "vastly improve the experience for our people who are committed to keeping New Zealanders safe".
"Saliva testing has the potential to reduce border-related public health risk by enabling more frequent testing. Furthermore, saliva testing may free up nurses from taking swabs and allow them to be redeployed to other areas of health response."