Rome's Colosseum, which is reopening its arena and underground after extensive restoration, needs more funding to survive in the long-term, a culture ministry official said after visiting the site.

"From now to August we will reopen the arena, the hypogeum (underground), the gallery between the second and third floors, and the attic," the technical director of the archaeology section in Italy's Culture Ministry said.

However, Piero Meogrossi also said it was indispensable to put in place a more ambitious project encompassing restoration, maintenance, surveillance, the creation of a museum, and pursuit of scientific research.

A €23-million plan supported by Rome's mayor, would include cleaning the façade damaged by pollution from an estimated 2,000 cars passing the monument each hour, but it still needs sponsors.

"More than sponsors, we prefer to talk of partners, because we would like them to get involved along with us," Mr Meogrossi said.

Pointing out that the number of visitors to the Colosseum per year has grown from one to six million in a decade, Mr Meogrossi deplored the lack of funds and staff at the Roman monument.

"We have a budget of between €400,000 and €500,000 a year for basic maintenance... there are checks, but not in a systematic way," Mr Meogrossi said, whose passion for the Colosseum goes back twenty years.

The monument, Mr Meogrossi argues, is too narrowly associated with gladiatorial combat and the idea of the Colosseum as a "sacred place where Romans celebrated the past so as to better project themselves in the future," should be restored.

Rome's Colosseum, the largest ever built in the Roman Empire and in use for almost 500 years, is an egg-shaped amphitheatre that was completed in 80 AD with a capacity of up to 75,000 spectators.