Americans have been advised to "reconsider travel" to New Zealand by the US Department of State Travel.
Similar to New Zealand's Safe Travel advisory, the US State Department provides information and advice on specific countries, which are assigned one of four 'levels'.
Level 1 (Exercise normal precautions), level 2 (Exercise increased caution), level 3 (Reconsider travel) and level 4 (Do not travel).
New Zealand has been assigned level 3, with the US State Department encouraging people to: "Reconsider travel to New Zealand due to COVID-19-related restrictions".
"The Centers for Disease Control and Prevention (CDC) has determined New Zealand has a high level of COVID-19," read an alert on the department website, stating there are restrictions in place that affect US citizens' entry into New Zealand.
Over the last month, New Zealand's Covid-19 cases have sat between 5000 and 10,000. On Monday, the Ministry of Health reported 6636 new cases and 480 people in hospital with Covid-19.
Currently, 44 countries, including New Zealand, are at level 3 in the US, as well as Vanuatu, China and Poland.
At level 3, citizens are encouraged to "avoid travel due to serious risks to safety and security."
Other advice includes reading the Country Security Report for New Zealand, preparing a contingency plan for emergencies, and enrolling in a Smart Traveler Enrollment Program (STEP) which makes it easier to receive alerts and be assisted in an emergency.
Australia, Fiji and the Cook Islands are currently at level 1.
On Monday, New Zealand opened their borders to visitors from around 60 visa-waiver countries, including the United States. This means people can now travel to New Zealand without isolation if they are vaccinated and do a pre-departure and arrival test for Covid-19.
Direct flights have already been arriving from places like Los Angeles and San Francisco.