Roger Ward, Colleges' Employers' Forum chief executive, was accused of acting against the merger spirit by telling his members how to vote on five issues connected with union with the Association for Colleges.
His action angered principals close to the Association for Colleges. It was seen as a breach of the two bodies' "ceasefire" agreement struck to prevent public bickering during delicate merger negotiations.
The AFC leadership maintained an official silence over Mr Ward's circular which was sent to CEF members but prominent supporters condemned the document which was branded by one commentator as being "scurrilous and offensive".
It was described as Mr Ward trying to score points for the CEF in the run-up to elections for the board of the new ABC - the Association of British Colleges, the name chosen for the merged body.
Mr Ward played down his circular, saying the "massive amount of agreement" outweighed the differences the document highlighted. Principals were under no pressure to take the CEF advice, he added.
The advice is not seen as an attempt to scupper the merger process, which has moved relatively swiftly after early delays.
Mr Ward's characteristically bullish approach contrasts with the reticence of the AFC. The AFC has told members it chose not to issue its own advice on the consultation process as it "wished to respect the autonomy of individual colleges". But after requests from member colleges it has drawn up a briefing paper. AFC leaders are now considering issuing firmer recommendations following the CEF stance.
Of the five issues AFC and CEF member institutions are being asked to vote on, regional involvement in the new ABC has exposed tension between the two organisations.
The AFC paper says that the joint committee agreed a two-tier structure was needed for the new body, but "agreed reluctantly" to defer introducing a second, regional tier.
But the CEF recommends members vote against a second tier, saying it would be "an inappropriate diversion of resources".
Cracks are also showing over the voting system for elections to the ABC board. In a move which has infuriated AFC members, the CEF bulletin calls the single transferable vote system - used by the AFC and the lecturers' union NATFHE - "costly and unnecessarily bureaucratic". The CEF uses the first-past-the-post system.
The two sides disagree on whether a number of places on the ABC board should be reserved exclusively for existing members of the CEF and AFC boards.
AFC leaders were annoyed by the tone of the circular. It described the 72 AFC-only member colleges as "a handful" and says the CEF is bringing a "business-minded level of practicality" to the debate.
Mr Ward denied he was attempting to damage the merger process, saying he was trying to bring reluctant colleges on board.