Zverev voluntarily went into self-isolatation after several tennis players tested positive for COVID-19 after taking part in Novak Djokovic's ill-fated Adria Tennis event last week. Zverev announced he had tested negative after the event's cancellation.
In an Instagram post, Kyrgios condemned Zverev's actions and labeled the world No. 7 "selfish".
"I see more controversial things happening around the world, but one thing that stuck out for me was seeing Sasha Zverev, again man, again. How selfish can you be? How selfish can you be?
"If you have the audacity to put out a tweet that you made your management f---ing write on your behalf saying you're going to self-isolate for 14-days, and apologising to the general public for putting their health at risk - at least have the f---ing audacity to stay inside for 14 days. My god.
"This tennis world's pissing me off, seriously. How selfish can you all get?"
Kyrgios has been vocal in his condemnation of Djokovic's decision to host the tennis tournament that saw the World No. 1, Grigor Dimitrov, Borna Coric and Viktor Troicki all test positive for coronavirus.
Players were witnessed partying at packed nightclubs before the event's final was canceled after Dimitrov tested positive for the virus.
Kyrgios has also been vocal in his criticism in the USTA's decision to host the US Open despite the continued rise of COVID-19 cases in the country.