"We are filling the stockpile in anticipation of a possible problem in the fall. We are doing everything we can beneath the surface, working as hard as we possibly can," Navarro told CNN's Jake Tapper on "State of the Union."
Asked by Tapper if the administration is preparing for a second wave in the fall, Navarro replied, "Of course."
"You prepare for what can possibly happen. I'm not saying it's going to happen, but of course you prepare," he added.
CNN has reached out to the White House for comment.
Navarro's comments come as Vice President Mike Pence, who's leading the Trump administration's coronavirus task force, has downplayed the threat of a second wave that public health experts are warning about.
In a Wall Street Journal op-ed last week, Pence blamed the media for inciting "panic" regarding a second wave of coronavirus.
"In recent days, the media has taken to sounding the alarm bells over a 'second wave' of coronavirus infections. Such panic is overblown," he wrote.