The project was due to be completed by the end of the year.
But sources have told the Enquirer that an Easter handover date is now being looked at once final testing is complete.
The delay would leave Vinci facing a heavy bill for liquidated damages that could run into tens of millions of pounds including labour and materials cost overruns on the £423m project.
Officially the team working on the project has told Nottingham Council that the project will be completed some time in the first half of next year.
Vinci said it had implemented a policy of reducing bidding for UK projects while the new management team focusess on completing its £232m civils element of the project.
Sources have told the Enquirer that some completed work on the delayed tram project has had to be ripped out and redone.
Several subcontractors have decided not to continue on the job.
An army of around 1,500 people is now understood to be battling to get parts of the phase two project finished.
Vinci said it expected to complete construction before the end of the year and it was working with its joint venture partner, concessionaire and other stakeholders to complete commissioning work to enable commencement of a full service as soon as possible.
The French contracting group warned that it had run into problems with several contracts in the UK after issuing a trading statement for the third quarter.
It said: “In the UK, problems with several projects, mainly the Nottingham tram extension, prompted the new management at VINCI plc to scale back activity.”
Investor relations director at Vinci Construction Christopher Welton said: “Our new management team is in place and concentrating on getting the problem project out of the way before they turn to developing new business.
“We don’t know what the exact timing of that will be.”
He said that voluntary scaling down of UK activity was responsible for an £80m fall in revenue in the third quarter.
Losses on the Nottingham Tramlink project will be a blow to Vinci’s UK construction business which has suffered losses of £34m and £7m in the last two years of reported accounts for its building arm.
Its civil engineering business, built from the former Taylor Woodrow civils arm, had escaped such problems remaining in profit as it grew rapidly in recent years from around £150m to close to £400m.
Earlier this month, the French boss of Soletanche Freyssinet Bruno Dupety was parachuted in to run Vinci Construction UK after chief executive John Stanion retired and managing director Andrew Ridley-Barker suddenly left the firm.