Rome's Leonardo da Vinci airport is flying again as Italy reopened regional and international borders in the final phase of easing its long coronavirus lockdown.

Families and loved ones separated by the global pandemic finally reunited but normality was a long way off as it remains an open question if other nations will accept Italian visitors now allowed to travel.

Italy is the first European country to fully open its international borders, dropping the 14-day quarantine requirement for visitors.

But most European nations see Italy's move - which aims to boost its collapsed yet critical tourism industry - as premature.

A horse-driven carriage waits for customers in an unusually uncrowded historical Piazza della Signoria square, in Florence. Credit: AP

Many European nations are moving to open only on June 15 - some even much later than that.

Who gets to go where in Europe this summer looks set to be determined by where you live, what passport you carry and how hard hit your region has been during the Covid-19 pandemic..

At Rome's international airport, Andrea Monti embraced his girlfriend, Katherina Scherf, in an emotional reunion as she arrived from Dusseldorf, Germany.

"We haven't seen each other since before the pandemic," Mr Monti said.

Still, the airport remained practically unused - even though Italy's national holiday on Tuesday normally kicks off the summer domestic tourism season.

A passenger has her temperature taken to check for symptoms of Covid-19 before boarding a train at Milan’s Central Station. Credit: AP

Rome's international airport had scheduled to handle several thousand passengers on Wednesday - a dramatic different to the 110,00 passengers on the same day last year.

Italy has now also resumed high-speed train service between regions for the first time since the lockdown in early March, checking departing passengers’'emperatures as they accessed the tracks.

Europe-wide, rules on cross-border travel are a patchwork of regulations if not a complete mishmash.

Germany said it plans to lift a travel warning for European countries from June 15 but it may still advise against travel in some cases - for example to Britain if quarantine rules there remain.

Germany issued a warning against all nonessential foreign travel in March.

The Ponte Vecchio Old Bridge is seen through a window of the Uffizzi Gallery museum, in Florence. Credit: Andrew Medichini/AP

The aim is to change that for Germany's 26 European Union partners - other countries outside the EU that are part of Europe's passport-free Schengen travel area, and Britain.

Austria said it is ending border checks with all its neighbours except for Italy, due to lingering concerns about coronavirus infections there, particularly hard-hit Lombardy.

Italy's neighbour, France, is also looking at opening its borders on June 15 - although French citizens who cross over in the meantime are no longer subject to quarantines upon their return.