Education Scotland is being lined up to take over the lion's share of responsibilities held by Scotland's Colleges, the umbrella organisation for further education.
The Government is proposing to strip Scotland's Colleges of its quality improvement, management training and continuing professional development functions and hand them over to the national body created last summer by the merger of Learning and Teaching Scotland and HMIE.
The proposal is contained in the Government's consultation paper, Putting Learners at the Centre.
The chief executive of Scotland's Colleges, John Henderson, warned: "Worst-case scenario, this would mean we would cease to exist in our quality-improvement role."
He is particularly concerned about the employment prospects of the 30-plus staff who work in the area of continuous improvement (two-thirds of Scotland's Colleges' workforce).
Transferring them to Education Scotland would not deliver "any discernible improvement in either efficiency or effectiveness", he said.
"I have sought to get assurances on the transfer of undertakings legislation, which usually means that when a function is transferred, staff also transfer under existing pay and conditions. I have had silence from the Government on that point, which is very concerning for the staff."
EIS general secretary Ronnie Smith said Education Scotland had become "almost like a snowball rolling down a hill, accruing responsibility".
"It is beginning to look a bit like a sort of omnibus organisation, a bit of a monolith, with a very big, diffuse and diverse range of functions," he added. "At some point we have to ask, `How far is Education Scotland going to go in becoming the only show in town in relation to Scottish education?'"
With the college sector facing unprecedented cuts to budgets and radical restructuring into regional groupings, Mr Henderson said it was important the focus on supporting the curriculum was not diluted.
Given Education Scotland's focus on schools and its close relationship with the Scottish Government, Mr Henderson is also concerned that specialist training in merger management and college leadership could be lost.
Once the regional college system was in place, the new boards should have a large say in what sort of sectoral support and governance training they wanted, he said.
A Scottish Government spokesman said: "We are taking the opportunity to evaluate the best arrangements for quality assurance and capacity building in the college sector, including the future role of Education Scotland and Scotland's Colleges."
The Government was gathering views and would consider all potential models early this year. "The provision of effective capacity-building support during a significant period of change will be an important part of these considerations," he added.
A spokesman for Education Scotland said it and its predecessors had a history of working with Scotland's Colleges in support of the sector.
"Since the post-16 review proposal was published, we have engaged in partnership with Scotland's Colleges on the implications of the various possible outcomes to ensure that any staff who may be affected are kept fully briefed so that Scotland's Colleges and Education Scotland can continue to deliver high-quality support to the sector," he said.
UNION'S CALL FOR NATIONAL PAY BARGAINING IN FE IS GIVEN BACKING
Education Secretary Michael Russell has backed calls by the EIS union for a return to national pay bargaining in further education, saying the issue will be considered alongside plans for a regional system of colleges.
"Of course, colleges employ their own staff and ministers do not have power to impose a bargaining system on independent employers," he said.
"That is why we will invite views early in the new year from both unions and employers on how positive and flexible consideration of the issue might take place."
EIS general secretary Ronnie Smith said wide variations in pay and conditions were "clearly not in the best interests of further education, its staff or its students".
Original headline: National body could take over FE functions