The head of Italy's tax collection agency was wounded to the hand and eye by a letter bomb on Friday, two days after Italian anarchists claimed responsibility for a bomb sent to the head of Deutsche Bank.

Equitalia's director general Marco Cuccagna detonated the device when he opened a letter at the agency's headquarters in Rome and has been hospitalised.

Prosecutors said they were launching an inquiry for suspected terrorism and were looking into a possible anarchist link.

A police spokesman said that the letter bomb had arrived by regular post.

Prime Minister Mario Monti issued a statement expressing "solidarity" and defending the activity of Equitalia at a time in which his government is proposing a series of painful tax increases and pension reforms.

"Equitalia has always carried out and is continuing to carry out its duty in full respect of the law," Monti said.

"It is essential for the functioning of the state, without which it would be impossible to provide services to citizens," he added.

Equitalia has become widely unpopular in a country where tax evasion is rampant but has also been accused of making mistakes with regular taxpayers.

"We are very worried about this morning's attack on Equitalia," said Emanuele Fiano, a lawmaker from the centre-left Democratic Party.

"We cannot be indifferent to the fact that this has happened at a time of extraordinary social problems for the country," he said.

"It is fundamental that democratic institutions are preserved, and protest and dissent are contained in a civil and peaceful confrontation," he added.

The attack comes after Italian far-left group FAI -- Federazione Anarchica Informale (Informal Anarchist Federation) -- claimed responsibility for a letter bomb sent to the chief executive of Deutsche Bank, Josef Ackermann.

German state police said the group had referred to "three explosions against banks, bankers, ticks and bloodsuckers" in a note hidden in the package.

The FAI has been behind a string of attacks on European institutions, including an attempted letter bombing at the European Central Bank in 2003.

In April, the FAI said it was behind a letter bomb that injured two people when it exploded at the offices of the Swiss nuclear energy association.

On the same day, an Italian military officer was wounded in an army barracks by a letter bomb apparently sent by the same group.

The FAI has also claimed responsibility for a letter bomb sent to a Greek top security prison where a number of far-left extremists are incarcerated.

It was behind a bombing campaign in Rome just before Christmas one year ago that injured two people at the embassies of Switzerland and Chile and also targeted the Greek embassy, sowing panic in the Eternal City.