A Leonardo da Vinci masterpiece left Italy for Japan Monday amid a continuing row about loaning such an important work.
A member of former premier Silvio Berlusconi's Forza Italia party chained himself to the Uffizi loggia to protest the move.
Senator Paolo Amato said he was protesting against the "arrogance" of Culture Minister Francesco Rutelli who, he claimed, "decided this all on his own".
Amato accused Rutelli of breaching a ban on "essential" pieces of Italy's cultural heritage leaving the country.
Rutelli responded by accusing Amato of seeking publicity and "making Italy look bad".
The superintendent of Florence's museums,' Cristina Acidini, said "I would have been the first to chain myself up if I thought we hadn't got the utmost guarantees about the painting's safety, or if it had been even slightly vulnerable".
She described the high-tech package in which the painting will travel - including Japanese-made sensors to detect any variation in position, temperature and humidity - as "a travelling laboratory".
Uffizi director Antonio Natali, who has consistently opposed the loan, did not attend the picture's sending-off but issued no comment.
Acidini said Natali had "come round" after his earlier opposition and was "working assiduously to make sure everything goes right".
Art lovers including film director Franco Zeffirelli also opposed the move.
The Annunciation has left the Uffizi three times before: for Paris and Milan in the 1930s and for safekeeping during the Second World War.
The painting, which has been insured for 100 million euros, will be the centrepiece of an Italian cultural and trade showcase, 'Primavera Italiana 2007', (Italian Spring) in Tokyo for the next three months.
It will be the star attraction at a show called Leonardo's Mind.
The Annunciation, one of Leonardo's early masterpieces, has been one of the top draws at the Uffizi since it moved there from a private collection in the mid 19th century.
Leonardo (1452-1519) probably painted it in 1472-75, when he was barely out of his teens.
Despite this, experts say it has a similar impact to mature masterpieces like the Mona Lisa and the Last Supper.
