In a statement released on Thursday, the Order - which oversees the profession in Portugal - said that it received 4,506 applications for certificates of equivalence to work abroad during 2019.

In 2018, the organisation received 2,736 applications, and in the previous year it was 1,286.

"Given the data from the first half of 2019, which saw 2,321 requests for declarations, the Order had already warned of the possibility of 2019 registering the largest wave of emigration ever, which eventually came to pass, and the year closed with surprising numbers and beyond the estimated ones," the note said.

The figure, the Order added, is "worrying" as it reflects the state of the health sector in Portugal and the way in which professionals are treated.

"Abroad, nurses have their training and specialism paid; they effectively have a career with differentiated salaries, but above all, are recognised and cherished," the statement quoted the head of the Order of Nurses, Ana Rita Cavaco, as saying.

As for the countries to which nurses are emigrating, the UK continues to top the list, followed by Spain and Switzerland. The United Arab Emirates is now in sixth place.

According to the Order, there are currently 18,000 Portuguese nurses working abroad, while in Portugal there is a shortage of some 30,000, according to its estimates.