Of the 20 dead, two people were in their 50s, and both had "serious underlying health conditions", Chief Health Officer Dr Kerry Chant said.
The other fatalities included six people in their 70s, seven in their 80s, four in their 90s and one person aged over 100.
Health Minister Brad Hazzard told vaccine "disbelievers" to "wake up to yourselves".
"The world is telling us that this virus will keep killing us and keep putting us in hospital, unless we get vaccinated," he said.
Mr Hazzard said "silly" anti-vaccination messages should be forgotten.
