Barclays has been accused of "playing games" with staff after it told workers at its processing plant in Poole, Dorset, that plans to move to a new site have been axed, raising fears over job losses.
Last May Barclays revealed plans to close its current facility in Poole - with the loss of around 1100 jobs - as part of an efficiency drive.
At the time the bank said it would move the remaining 900 staff to a new building in the area in 2010.
However, following a review of the costs of relocating to and occupying the new building, Barclays has now told staff it will stay at its current site.
The bank insists it is committed to the area and is looking at options to improve the Barclays House office.
But financial union Unite says the bank has refused to respond to requests for written assurances that jobs are not under threat.
The union says it has "real concerns that the job security of staff will be in question after 2010 when the new site was due to be opened".
In a statement, Barclays only says that it "continues to expect to have approximately 800-900 staff on site in 2010".
Graham Goddard, deputy general secretary, Unite, says: "Unite want Barclays to stop playing games with their workforce and make their plans for the 900 staff in Poole clear. We can not have a situation where staff have no faith that they will have a job in two years times."
The latest fears over job losses come just days after it emerged that Barclays plans to cut around 1800 technology jobs in the UK over the next couple of years as it looks to offshore the work to "centres of excellence" around the world.
Staff at the bank's global infrastructure and service delivery (GISD) unit were informed of the plans in January, with the bank expected to shift the work to facilities in India, Hungary and Singapore.