Frederiksen made the announcement on her arrival in Brussels for an EU summit, Danish media reported.
“We have purchased quite a few vaccines, so we have scope to vaccinate the Danish people, revaccinate in the autumn if necessary and donate vaccines,” Danish news agency Ritzau quoted Frederiksen as saying.
Frederiksen said Denmark had not yet decided which vaccines would be donated to Covax.
The Scandinavian country was the first in Europe to discontinue the use of the vaccines made by AstraZeneca and Johnson & Johnson due to concerns about a rare but serious form of blood clots, but has since made both shots available to volunteers.
The country is using the Pfizer-BioNTech and Moderna jabs in its vaccination programme.
The epidemic is considered under control in Denmark and the majority of people at risk and health professionals have been vaccinated.
According to the latest figures, 20 percent of Denmark’s population of 5.8 million are fully vaccinated while 32 percent have received the first dose of the vaccine.
Frederiksen said meanwhile that she expected EU heads of state and government to agree at the summit to donate a total of 100 million Covid vaccines to Covax.