"Do not underestimate the danger," Poland’s Chief Sanitary Inspectorate warned on Twitter.
It added: "Nearly a quarter of coronavirus infections in Poland are people under 30! Think about whether you REALLY need to leave the house. Don't put your life and the lives of your loved ones at risk.”
A total of 22 people in Poland have died from the Covid-19 disease, while 1,862 have been infected, officials said late on Sunday.
Reports of young people ignoring health warnings and meeting up with friends during the epidemic have caused concern in Poland.
Poles have been told by the authorities they cannot gather in groups of more than two, though families are exempt from the restriction.
The country’s first coronavirus infection was confirmed by officials on March 4, while the first coronavirus fatality was announced on March 12.
Poland has declared a “state of epidemic" and temporarily closed its borders to non-residents in a move to curb the spread of the illness.