The announcement has come in the final hours of Tonga's seven day lockdown following it's first covid scare.
The Vaccination Act Amendment 2021 has been signed by King Tupou the Sixth making it compulsory by law to get vaccinated.
Tonga's Ministry of Health said it would only exercise this new power if there's the risk of an infectious disease spreading out of control.
Tongatapu has just finished a seven day lockdown after a passenger arriving from Christchurch tested positive becoming the Kingdom's first covid case.
More than 300 passengers and frontline workers remain in 21 days managed isolation.