The Prime Minister, Tuilaepa Sailele Malielegaoi, announced the measures will be in effect for 14 days.
The Samoa Observer newspaper reported the order included the shutting down of the border for all except returning Samoan citizens.
There have been restrictions placed on public gatherings to a total of five.
Public transport is to be temporarily halted with nightclubs, restaurants and cinemas also closed.
Travel to the island of Savai'i has been limited to just three days a week.
Non-essential public servants are also having their hours reduced.