Ensuring pay parity between further education lecturers and school teachers in Wales could cost another pound;9 million over the next three years - at a time of frozen and declining budgets.
John Graystone, chief executive of fforwm, which represents Welsh colleges, said the Assembly government's policy on the issue was inconsistent.
Speaking at fforwm's annual conference in Llandudno yesterday, he highlighted a "policy which supports pay parity but which, after the initial funding for pay, suddenly disappears".
He said: "Do we revert back to every college paying different pay levels? We calculate long-term incremental costs to be around pound;9m by 2010."
The Assembly government has provided pound;32m over the past three years to help harmonise pay between the two sectors. But costs are likely to creep up as FE staff progress through their own "threshold" to an upper pay spine.
Dr Graystone noted 18 colleges received a frozen budget this April, with an overall sector increase of some 0.46 per cent - compared with 2.78 per cent for schools. Colleges were expecting to benefit more from a new funding system which applies to both schools and colleges providing post-16 education.
"The good news - your budgets are frozen," he told delegates. "The bad news? Your budget will decline every year up to 2010, and we want you to increase participation, raise standards and take on new initiatives."