"This is a woman that's deeply unwell, and clearly needs some help," Ocasio-Cortez told reporters when asked about Georgia Representative Marjorie Taylor Greene.
The Washington Post this week reported two of its journalists witnessed Green aggressively confronting Ocasio-Cortez this week.
U.S. Democratic House Speaker Nancy Pelosi said Green committed "verbal assault and abuse," and may have violated ethics rules of the U.S. House of Representatives.
Greene already has been sanctioned by the House for making incendiary remarks, including promoting violence against Democrats.
The Republican on Friday said voters in her district wanted her to debate policy with New York progressive, accusing Ocasio-Cortez of promoting "socialism."
"I know for a fact what socialism will do to our country," Green told reporters. "The American people know it. The American people want to see a debate."
Greene has voiced support for unfounded conspiracy theories including the "QAnon" one that holds that elite Democrats are part of a cabal of Satan-worshipping pedophiles and cannibals.
She has since distanced herself from some of her remarks.
A CNN reporter on Friday shared since-deleted footage on Twitter purporting to show Green in 2019 - before she was elected to Congress - harassing Ocasio-Cortez through the mail slot in the Democratic representative's office door.