Cuts mean grand archaeological find may be buried to save it from pollution and ice.
On its discovery in 2008, it was hailed as one of the most significant Roman finds in decades.
Digging down between the railway line and mechanics' workshops where the Tiber winds its way north out of Rome, archaeologists found the remains of a 13m-high structure fronted by four columns.
This was what was left of the luxurious tomb of Marcus Nonius Macrinus, the swaggering Roman general whose ceaseless campaigning in the 2nd century helped inspire Russell Crowe's film Gladiator.
But now cuts mean the tomb may be reburied all over again, according to Rome's extremely unhappy state superintendent for archaeology. "I fear we are going to take into serious consideration the idea of protecting these sensational finds by recovering the entire site with earth," said Mariarosaria Barbera.
Today, Macrinus' last resting place - in an industrial wasteland in the suburbs of Rome - appears forgotten. Delicately carved white capitals miraculously preserved for 1800 years under thick clay now sit, discoloured by air pollution, in pools of rainwater, while cracks caused by winter ice have appeared in the stonework.
With funding for maintenance of Italy's archeological sites slashed by 20 per cent since 2010 thanks to austerity cuts, the sum of between €2 million ($3.1 million) and €3 million needed to preserve the tomb would not be available unless a sponsor was found soon, said Barbera.
Covering up precious discoveries to protect them is getting more common in Italy as funding shrinks, she added. "Until now it has usually happened when remains are not that significant or monumental. In this case they clearly are."
A trusted friend of Emperor Marcus Aurelius, Macrinus won his spurs fighting Germanic tribes, just like Crowe's character, which was enough for the site to be known as "the Gladiator tomb".
Beyond that the similarities end, since Macrinus did not fall out with the emperor's son nor become a gladiator but died a rich man, honoured by his huge mausoleum.
"The tomb was very grand, with marble roof tiles, not terracotta, and was probably inspired by what he saw in Turkey," said Daniela Rossi, the archaeologist who has led the dig and written a book about the finds.
A panel carved with Latin script spelling out Macrinus' military career has been dug up, revealing for the first time that he also travelled to Spain.
The discovery also raises new questions about the importance of the Via Flaminia, the Roman consular road running alongside the mausoleum which experts believe was flanked by tombs and rivalled the better known Appian Way.
A stretch of the perfectly preserved, stone-flagged road dating from Rome's republican era - which was exposed by the dig - abruptly disappears under a railway line at one end of the site and beneath an abandoned house on the other.
"This is an extraordinary site, it blows you away," said Darius Arya, an American archaeologist who has worked at the tomb and is campaigning to keep the bulldozers at bay.
"Burying these remains is a disaster - you wonder what is the point of archaeology."
Maria Grazia Vernuccio, a spokeswoman for the heritage group Italia Nostra, said funding cuts were leaving several Italian sites at risk of crumbling, from Pompeii to the sprawling city of Ostia Antica near Rome, to Villa Jovis, the Emperor Tiberius' palace on the island of Capri, and Aquileia, the Roman city near Venice.
"Over 40 per cent of Italy's archaeological sites are now closed due to lack of funds," she said.
"Inspectors often cannot even get to the more remote sites ... because the ministry won't give them petrol and there is less money for guards."
Work could start any day if temperatures fall and the risk of ice damage increases.
Marcus Nonius Macrinus
Who: Roman general and consul, proconsul of the Roman province of Asia, adviser to Emperor Marcus Aurelius
Tomb discovery: In October 2008 his tomb was found by the River Tiber north of Rome. It is now being reburied because of lack of funds for reconstruction.
- ObserverBy Tom Kington