Portugal will open to tourists from nearly all European countries from Monday, the interior ministry said, following months of restrictions to prevent the spread of COVID-19.

Travellers from EU countries with coronavirus rates below 500 cases per 100,000 residents during the last 14 days can make "all types of visits to Portugal, including even non-essential visits," the ministry said in a statement on Saturday.

It said restrictions, limited to essential trips, would be maintained for five EU countries -- Cyprus, Croatia, Lithuania, the Netherlands and Sweden.

It stressed restrictions also remained on non-European countries including Brazil, India and South Africa.

"We're not opening tourism to the whole world. Restrictions remain for third countries," a ministry spokeswoman said.

Restrictions are lifted for "passengers from the European Union, the Schengen Area and the United Kingdom," provided their rate is below 500 cases per 100,000 residents, the spokeswoman said.

The Schengen Area covers 26 European countries, most of them in the European Union.

Under the rules, all passengers above two years old heading to the country will still have to present a negative PCR COVID-19 test taken within 72 hours before embarking.

Airlines that allow passengers to embark without the test will face a fine between 500 euros and 2,000 euros per passenger.

The announcement came a day after Lisbon lifted restrictions from visitors from Britain, which accounted for some two million annual visitors to the country before COVID-19 hit.

Portugal and Britain currently have two of the lowest virus rates in Europe.

The return of tourism follows a disastrous year for the sector in 2020 and is key to the country's economic recovery.

Last year tourism accounted for 6.3 per cent of Portuguese GDP, as opposed to 11.8 per cent the previous year.