Dr Ashley Bloomfield says there was "dissonance" between the Ministry of Health and the Government over the scale at which border staff were being tested for COVID-19, but denies politicians were misled over the extent and scope of the regime.
In June as part of "targeted surveillance testing", people who work at the border were due to be tested to ensure the wasn't undetected infections among staff.
However, a Newshub investigation found nearly two-thirds of all border and managed isolation and quarantine workers in Auckland had never been tested for COVID-19 a week before the outbreak.
On Saturday, all 12,000 staff across the Auckland and Tauranga ports were ordered to help rule out where the latest outbreak may have come from.
Dr Ashley Bloomfield says the testing across all border staff required "a lot of coordination" with the Ministry of Health, those in charge of managed isolation and quarantine facilities, and people managing a range of workforces at airports.
"We were giving the Minister [of Health] and Cabinet very regular updates on the extent of that. And based on our updates, they were again making sure on a very regular basis that we were quite clear about the imperative to get the testing scaled up as quickly as possible for our border workers as one part of continuing to strengthen our border measures," he said on Monday.
"It was being implemented, and as I say, this was quite extensive testing across a number of sites, a number of workforces."
But Dr Bloomfield says when providing these updates to Cabinet and the Health Minister, it may have been miscommunicated.
"There was clearly a dissonance between what the Prime Minister thought was happening and what was happening on the ground, but that doesn't mean we weren't providing full information through.
"Just think about this as part of the suite of actions that were underway but we couldn't suddenly flick a switch and test all members of that workforce overnight."
He says testing was happening, but he wanted to communicate the "challenge and complexity" of trying to roll that out.
The scaling up of testing for border staff began while New Zealand was in alert level 1, and at that time testing was voluntary. Dr Bloomfield says border workers "didn't necessarily feel" they had to get a test, particularly because they were being checked for symptoms on arrival at work each day.
However, now there's an order requiring they be tested, the workers have been coming forward and are "very cooperative".
Health Minister Chris Hipkins said last week he would've liked to see more border staff tested earlier, but compulsory testing was a "big lever to pull".
"I think the Government exercises a great deal of caution in making it compulsory for everyone to undergo a medical procedure," he said on Friday.
