Historic bones have been found on Shambles in York.
It means that the work to install the anti-terror bollards has been delayed.
That has dismayed Shambles traders who say their takings are down due to the restrictions, which have seen one end of the famous street is closed to pedestrians.
A City of York Council spokesperson said: “From next week on the Shambles, work will take place from 8am to 7pm Monday to Friday, and 8am to 4pm on Saturdays.
“This is due to archaeological finds of bones and challenging ground conditions.
“The historic bone fragments are likely to have been part of the neighbouring St Crux burial ground and have been sent for analysis with York Archaeological Trust.”
The contractor aims to reopen pedestrian access on one side of the Shambles/Pavement junction “as early as possible in the week commencing 2 October”.
Meanwhile the work on Goodramgate has also been delayed. “This is due to having to work around complex, existing underground pipes and cables which is extending the work by three weeks until 13 October,” says the council.
Working hours on Goodramgate will also be extended and match those on Shambles.
James Gilchrist, director of transport, environment and planning, said: “I want to apologise for this delay and the disruption to city centre businesses and residents while we install these hostile vehicle measures.
“We continue to work with our contractors to maximise access while minimising delays.
“Working in a historic city centre, we are always mindful of unexpected findings as our work at Shambles and Goodramgate has shown, which is why we’re upping our contractor’s working hours to help mitigate the impact.”
Cllr Peter Kilbane, executive member for transport and economy, said: “We are sorry that the work is having to extend and we’re taking all feasible measures to balance timescales, disruption and project costs.
“This infrastructure is in place to protect the city and while we are supporting businesses with additional signage and partnership promotions, we understand and apologise for its impact.”
Businessman Phil Pinder, of the Shambles Area Traders’ Association, told YorkMix that takings at his shop The Potions Cauldron were down 20% in the first week of the roadworks.