EUROPEAN Parliament president David Sassoli has died aged 65 in Italy.

The journalist, who worked his way up in politics while defending the downtrodden and repressed, died in hospital in Aviano, north-east Italy, early on Tuesday, his spokesman Robert Cuillo said.

Sassoli had been in hospital since December 26 due to abnormal functioning of his immune system.

EU Council president Charles Michel called Sassoli a "sincere and passionate European. We already miss his human warmth, his generosity, his friendliness and his smile".

The Italian was first elected at the European Parliament in 2009. He won another term in 2014 and served as the Parliament's vice president, before taking the top job five years later. He had decided not to run for re-election, with a new president to be appointed later this month.

The socialist had been struggling for months with poor health, yet stayed on the job, where his vigour and easy smile were a trademark.

Sassoli had suffered pneumonia caused by the legionella bacteria in September.

His health steadily declined afterwards and he was forced to miss several important legislative meetings.

He was at his strongest when he took up the cause of migrants who died crossing the Mediterranean or dissidents such as Alexei Navalny, who is taking on the Kremlin from a jail cell.

The National:

In recent months, his condition had improved enough to preside over a European Parliament session in December to give the EU's main human rights award, the Sakharov Prize, to Navalny's daughter.

High in symbolism, this act became his political testament.

EU Commission president Ursula von der Leyen wrote on Twitter: "I am deeply saddened by the terrible loss of a great European & proud Italian.

"David Sassoli was a compassionate journalist, an outstanding President of the European Parliament and, first & foremost, a dear friend. My thoughts are with his family."

Sassoli is survived by his wife, Alessandra Vittorini, and his children, Livia and Giulio.

Italian premier Mario Draghi sent condolences on behalf of the Italian government and paid tribute to Sassoli as "a man of institutions, a profound pro-European, a passionate journalist - Sassoli was a symbol of balance, humanity, generosity".

The head of Sassoli's Democratic Party and a long-standing friend, Enrico Letta, praised Sassoli's European passion and vision and vowed to carry them forward, though "we know we're not up to it".

The National:

In a tweet, Letta called Sassoli "someone of extraordinary generosity, a passionate European" and a man of "vision and principles, theoretical and practical".

Roberta Metsola, the Christian Democrat who was set to take over from Sassoli next week, said: "I am heartbroken. Europe has lost a leader, I have a lost a friend, democracy has lost a champion."

She said Sassoli "dedicated his life to making the world a better, fairer place".