The National Association of Head Teachers was enraged by draft guidance for governors on changes in heads' pay structure. It is demanding radical changes in the document, before it is circulated to governors and heads later this month.
The Government's determination to reward the best heads is reflected in a new pay scale which schools must implement this term, offering salaries of up to pound;70,000. For the first time, governors also have a statutory duty to link pay to performance.
The Department for Education and Employment is consulting unions and governors' representatives on a draft of the guidance to go out to heads and governing bodies.
But David Hart, general secretary of the NAHT, said: "The guidance is unacceptable. If it does not go out with some fairly significant revisions, we would be advising our members it is something they should not be applying."
Mr Hart said he was furious that the 15-page document confuses the roles of heads and governors. It says "all governing bodies have responsibility for recruiting, employing and managing staff". This was not true, said Mr Hart - management was the head's responsibility.
He said: "The document is stunningly patronising. It says 'you as governors are acting as the guardians of the education of the young people in your school'. No one needs to be told that."
Margaret Riddell, co-director of Information for School and College governors, said: "We are furious about the section which says that governors should be managing staff."
Pat Petch, chair of the National Governors' Council, said she hoped changes would be made before the document was distributed to schools.