A £7.6m shortfall means Colchester's firstsite:newsite looks unlikely to open until 2010 - seven years after it was commissioned.
The arts centre was due to open this autumn, but construction stopped for nine months at the start of the year after the £17.8m budget was exceeded.
Work to weatherproof the structure by May 2009 has started, but fitting out the building needs more cash.
Martin Hunt, Colchester District Council's deputy leader, said: "The funding partners are in negotiation to provide extra funding for the fit-out. When talks are over, tenders will be sought for completion of the work, hopefully by Christmas 2009 or spring 2010 at the latest."
The arts centre was due to open this autumn, but construction stopped for nine months at the start of the year after the £17.8m budget was exceeded.
Work to weatherproof the structure by May 2009 has started, but fitting out the building needs more cash.
Martin Hunt, Colchester District Council's deputy leader, said: "The funding partners are in negotiation to provide extra funding for the fit-out. When talks are over, tenders will be sought for completion of the work, hopefully by Christmas 2009 or spring 2010 at the latest."
