The Scottish Funding Council (SFC) said £25m had already been provided to support the policy, with an additional £20m pledged over the next two years.
However, the figures, submitted to the Scottish Parliament's public audit committee, do not include the costs paid by individual colleges from their reserves – which could be close to half the overall figure.However, SFC officials also believe the policy will have delivered savings of at least £57m by 2014/15 – and as much as £107m by 2016.
Mark Batho, chief executive of the SFC, said: "On our current estimates, the aggregate of potential merger efficiencies in these years means that these savings are achievable."
John Henderson, chief executive of Scotland's Colleges, welcomed the additional money. He said: "We are pleased the SFC has stated the importance of providing ongoing and realistic levels of financial support."