The contractor sealed a pre-construction services deal for the job in April.
But Bristol City Council has new ordered consultants at KPMG to widen the scope of their value-for-money review of the proposed 12,000 capacity arena.
KPMG will now look at the “location, design and the possibility of private financing as part of a thorough assessment of options.”
The results are expected next month, with a decision on how to move forward with the project expected at a council cabinet meeting in January.
The council added: “Buckingham’s work will now be paused until the KPMG review is received and considered.
“A pause at this stage of the pre-construction phase of a project is not unusual and it means the council will not be paying a contractor whilst there is no final decision on how to move forward.”
Marvin Rees, Mayor of Bristol said: “Buckingham have done a good job and we now need to see what the wider review of the project says.
“I remain 100% committed to delivering an arena for Bristol and with this in mind it is right to look at every available option, along with the benefits and drawbacks of each.
“We can’t commit to the current design on this specific site at any cost and I wouldn’t want that kind of blinkered approach to become the arena’s undoing”.
“A lot of work continues to go into the project and this pause shouldn’t be mistaken for a backwards step.
“We’re operating to the same decision-making timeline that’s been previously announced. This is about doing the sensible thing in looking at all of the possibilities and being open minded about where the advice received takes us.
“Whatever happens the arena will become reality and we remain on-track for a report to Cabinet in January.”
The current projected budget for the arena is £123.5m, for which funding is available from the Economic Development Fund (£53m), operator contribution and income (£42.5m) and infrastructure funding associated with the wider Temple Meads East project(£28m).
The council said: “Building the arena to its current design on the proposed site remains highly likely to cost significantly more than this, although the precise target figure is commercially sensitive and remains confidential.”
Rees added: “What we’re seeing with the cost is a challenge and we need to deal with it. I’ve asked our consultants KPMG to consider every avenue.
“This includes raising private investment, thinking about other sites and considering designs which could be delivered within budget. Nothing is off the table because one way or another this city is going to get an arena it can afford.”
“The current target date to open the arena is 2020 and this remains the case. It will, however, depend on what options are recommended by the council’s consultants and what future decisions are made.”