The US is advising citizens to avoid travelling to Malta, adding it to its highest-risk category for travel.

In its weekly update of COVID-19 travel notices, the US Centers for Disease Control and Prevention advised against travel to Malta, Moldova and Sweden as it added them to its "Level 4: Covid-19 Very High" category.

The CDC places a destination at Level 4 when more than 500 cases per 100,000 residents are registered in the past 28 days.

“If you must travel to Malta, make sure you are fully vaccinated before travel,” the advisory reads. 

“Because of the current situation in Malta, even fully vaccinated travellers may be at risk for getting and spreading COVID-19 variants.”

Malta, which has this month been experiencing daily record surges in confirmed virus cases, was previously at Level 3, considered "high risk."

The country reported almost 1,300 new virus infections on Tuesday - a national record. On Wednesday morning, Times of Malta reported how between 20,000 and 30,000 people were stuck at home in quarantine. Employers are warning that unless action is taken, the number of people unable to go to work could cripple the economy.  

The government has been facing calls to tweak the mandatory quarantine period.