"We were increasing the frequency of that testing."
He said the ministry was working closely with DHBs to ramp up testing.
Asked about people waiting up to five days for test results, Bloomfield said that tests were prioritised if they were more likely to be positive, and people were told about positive results "very quickly".
Bloomfield said he was giving the Health Minister and the Cabinet "very regular updates" about testing border-facing workers.
"I was checking every single day. There was clearly a dissonance between what the Prime Minister thought was happening and what was happening on the ground."
He said there may have been some miscommunication.
"We were under alert level 1 and we were going through a process of scaling up testing availability."
Asked about the Government's testing strategy - from June 23 - was for regular testing of asymptomatic border-facing workers, Bloomfield said: "We couldn't just flick a switch and do that overnight."
He said there had been no failure of testing of frontline border-facing workers, even though Health Minister Chris Hipkins has said that it wasn't happening as Cabinet expected, and Hipkins has taken responsibility for that.
Ardern has also said it wasn't happening as Cabinet had expected, though she said this morning it was unfair to assume that Bloomfield had misled her.
Bloomfield said no one had misled anyone, and that in his communications with ministers it was clear that Cabinet wanted regular testing of border-facing workers - which was being rolled out.
Asked about conflicting advice for testing Tauranga port workers, he said some of the workers will be deemed as higher risk than those, for example, simply driving truck drivers in and out of the port.