Health Minister Andrew Little said in Parliament it was "ridiculous" for National's deputy leader Dr Shane Reti to suggest he take responsibility for the Middlemore Hospital COVID-19 case slip-up.
"Does he accept that ultimately he is responsible for the coronavirus situation at Middlemore Hospital and not health staff?" Dr Reti asked Little on Wednesday.
"I don't think I've heard a more ridiculous question in this House in the time I've been in Parliament," Little replied. "I mean, we have a health system that has geared up to respond to the biggest pandemic the world has seen."
House Speaker Trevor Mallard described Little's response as "not entirely parliamentary".
Middlemore Hospital has been forced to stand down 29 staff for 14 days after failing to isolate a symptomatic patient who later tested positive for COVID-19.
"We know that 29 health personnel have been stood down. We know that another three patients who were in the room are regarded as close contacts and are isolating and are being tested," Little said in Parliament.
"And we know that there are family members who have been tested as well."
Little said the clinical decision was made "to leave him where he was", despite the fact he had shown symptoms of fever. "The judgment was that would be sufficient to contain any risk that he presented."
After the man returned a positive test, he and the three other people in the room were moved to isolation rooms, Little said.
"I am not the frontline clinician, in this case, nor for that matter, is that member. I trust our frontline clinicians to make the judgments that they do in the circumstances that they are in the middle of a pandemic."
Little said Counties Manukau DHB has "responded extremely well" to the call to prepare for COVID-19 outbreaks. He said the DHB "actively participated" in regional and national readiness preparation work.
He said as of June, the DHB had trained more than 100 full-time equivalent nurses for ICU cover, and 80 percent of its staff had been tested in relation to the COVID-19 positive patient on a ward and Middlemore Hospital.
"I'm satisfied that the clinicians at Middlemore Hospital made clinical decisions that they based on the best information they had at the time."