Araujo’s comments come as travellers rush to return to the UK from Portugal before the it is formally placed on the UK’s amber list from 4am on Tuesday (8 June).
Those returning from Portugal must have proof of a negative Covid test taken no more than three days before their departure or face a £500 fine.
However, long delays have been reported at testing centres in Portugal owing to the sudden demand, including waits of up to four hours at Faro.
Following last Thursday’s announcement, Araujo said: "We are extremely disappointed to hear the UK government has made the decision to remove Portugal from the green list.
"We fully maintain and stress unwavering confidence in the safety of the nation and thank the support of all our partners and friends in the UK, especially our trading partners that have been essential in quickly reinstating flight capacity into Portugal."
He said the country was fully prepared to welcome tourists and all necessary precautions were being taken to ensure the safety of visitors and residents.
Araujo said Portugal had been cautious in its management of its own Covid epidemic, and stressed the country had one of the lowest rates of new Covid-19 cases per head of population in Europe.
"Our country is among the European countries with the highest proportion of national testing and our vaccination strategy aims to have the entire adult population inoculated by August," he added.
"Our optimism remains unaffected and our stance clear. We are more than ready to safely welcome visitors, especially the British, and we will stand by our mission of providing the best touristic experience with the highest safety standards."
A spokesperson for British Airways said any customers currently in Portugal, who wish to return before Tuesday, can change their flights without charge.
"We have added additional flights from Portugal to the UK and increased capacity where possible, including operating a Boeing 777 aircraft on Monday," said the spokesperson.
EasyJet has also laid on my flights back to the UK from Portugal, upping capacity by around 1,000 seats.
