The White House rebuked the top US health agency on Sunday, saying "it let the country down" on providing testing crucial to the battle against the coronavirus outbreak.
The Centers for Disease Control and Prevention has been under intense scrutiny since producing a faulty test for COVID-19 that caused weeks of delays in the US response.
Critics have pointed out that it could simply have accepted kits made by the World Health Organization, which has been producing them since late January, instead of insisting on developing its own test.
"Early on in this crisis, the CDC, which really had the most trusted brand around the world in this space, really let the country down with the testing," Navarro told NBC's "Meet the Press."
"Because not only did they keep the testing within the bureaucracy, they had a bad test. And that did set us back."
The Food and Drug Administration has also criticized the CDC for not following its own protocols in manufacturing COVID-19 tests. The errors were not corrected until late February.
Trump often blames the administration of his predecessor, Barack Obama, for passing on "broken tests" for the new coronavirus -- although Obama left office years before the virus came into existence.
But Navarro's comments mark the strongest criticism by a named White House official of the CDC's role in the administration's slow roll-out of testing.
Health and Human Services Secretary Alex Azar defended the CDC against Navarro's criticism, telling CBS it was never meant to be "the backbone of testing, of broad, mass testing, in the United States."
"I don't believe the CDC let this country down. I believe the CDC serves an important public health role. And what was always critical was to get the private sector to the table," he said on "Face the Nation."
The United States has the world's largest coronavirus outbreak by far, with more than 88,000 deaths among some 1.5 million confirmed cases, according to Johns Hopkins University.
On March 6, Trump said as he toured the CDC headquarters in Atlanta that four million "beautiful" testing kits would be available within a week and that "anybody that needs a test gets a test."
More than two months later, just 12 million Americans have been tested -- less than four percent of the population.
That places it 39th in the world behind other hard-hit countries like Russia, Italy and Spain, according to trusted online statistics source Worldometer.
Experts say widespread testing -- of healthy people as well as those with symptoms -- is crucial as a means of knowing exactly where the virus is spreading as the US begins reopening the world's biggest economy, locked down during the health crisis.
Navarro accused China -- where the outbreak started late last year -- of crippling the US economy "in 30 days" but vowed that Trump would rebuild it as the country reopened.
Echoing a claim made frequently by the president, Navarro said locking down the country until the outbreak was over would kill "a lot more people" through suicides, drug abuse and a halt on medical procedures than the virus itself.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)