Anyone over the age of two years should also wear a well-fitting mask in all indoor public spaces, says the CDC website.
Destination-specific levels are based on several factors, including testing rates, vaccination rates, new variants and the number of new cases reported per 100,000 people over the last 28 days.
Level 4 places have more than 500 cases, Level 3 has between 100 and 500 cases and Level 2 has between 50 to 99 cases.
In the last 7 days there have been 861 infections reported per 100,000 people in New Zealand according to Reuters.
This led to New Zealand meeting the Travel Health Notice threshold - reseverd for countries that record a higher level for 14 consecutive days, or face a significant increase in cases in a shoter time frame.
New Zealand's risk level will be reviewed over a period of 28 consecutive days before it can be reinstated to Level 2.
This isn't the first time New Zealand has been classed as a Level 3 destination. Last year the country was classed as "high risk" due to strict border closures.
Currently, there are 140 destinations classed as Level 4 including Australia, Canada, and the UK.
Just six countries are classed as Level 1, low risk; Benin, China, Falkland Islands, Hong Kong SAR, Sierra Leone and Taiwan.
The 3-level notice system was adapted to a 4-level system in November 2020, as a way to communicate the health risks involved with travel to certain destinations.