Years of neglect at the ancient Roman city of Pompeii are being dug and scrubbed away in a last-minute bid to keep money flowing from a huge European Union-backed renovation programme.

Tourists visiting the Italian World Heritage site now peer through screens and wire fences at ruins of ancient houses where restorations are going into overdrive.

Submerged under volcanic ash when Mount Vesuvius erupted in 79 AD, Pompeii is one of the most visited archaeological sites in the world, attracting more than 2.5 million visitors a year. But years of mismanagement and corruption have exacerbated decay at the sprawling site, prompting the European Union to intervene.

In 2012, it pledged €78m (£57m) to finance urgent repairs. Italy threw €27m behind the Great Pompeii Project, which aims to rebuild collapsed arches, sagging walls, clean frescoes and protect the site from water-logging.

But only €21m of the total €105m has been spent. Unless the site managers do the rest of the work by the original 31 December deadline, they risk losing access to the money. “We are really working against the clock,” said superintendent Massimo Osanna, an ex-university professor chosen by the government to take over in early 2014. “If the timing had been respected more at the beginning we wouldn’t have this concentration of work that is causing problems now.”

The project has been plagued by squabbles over who should lead the work and extra checks were put in place to keep contracts from falling into the hands of the mafia. Mr Osanna said the pace of work has almost doubled since late 2014. “Visitors find houses closed, construction sites open, and it is difficult to get around,” said Stefano Vanacore, who has directed the restoration of several homes of ancient Pompeians. “If it weren’t for the December deadline we would have done everything more gradually,” he said.

Some 20 new technicians have been hired, but there is still not enough help said architect Maura Anamaria. “Each of us needs help and you cannot satisfy everyone’s demands. There are too many sites open and each one is complex.”

A third of the city has never been excavated and soil movements threaten the fragile ruins. Earlier this month, heavy rain raised the floor in the house of Roman nobleman Julius Polybius. The European Commission said it was more concerned with the quality of work than the time-frame as it is a high-profile sign of how well the EU’s regional funds can work.