Heads are concerned that Ofsted's plans to conduct staff questionnaires as part of school inspections from September could lead to them being marked down as "weak" leaders.
A document published by the schools' watchdog this week suggested staff surveys, being trialled as part of its new inspection framework, would provide useful evidence, along with schools' self-evaluation, of key points such as capacity to improve.
But the evaluation of pilot inspections carried out before Christmas also uncovered serious reservations among school leaders.
"Headteachers mentioned that negative views might be misinterpreted as `weak leadership' in situations where leaders were trying to influence intransigent staff," the Ofsted document says.
"It was accepted that the questionnaires would raise issues on which the inspectors would need to find further evidence."
Mick Brookes, general secretary of the National Association of Head Teachers, shares their concerns. He said any staff surveys had to be taken in the context of what was happening in the rest of the school.
"The endorsement of the staff doesn't necessarily mean that the leadership is strong," he said. "You can have a country club atmosphere in a school where everybody is cosy and happy, but that doesn't necessarily mean good leadership. On the other hand, you can have a head taking action against some members of staff who is very strong."
Ofsted already surveys parents as part of school inspections, but is considering extending these surveys to pupils as well as staff.
The watchdog's trials revealed fears that the reliability of young children's responses could be "unduly influenced by isolated, recent events".
There were also concerns about the accessibility of the surveys for pupils with learning difficulties and the very young.
Other ideas proposed for the new framework include the controversial no- notice inspections, more lesson observations and greater participation of school leaders in the inspection process.
During the trials, Ofsted found some inspectors had concerns about the extra workload caused by closer working with school leaders during inspections.
Both schools and inspectors noted practical problems with no-notice inspections, such as the need for heads to gather evidence at the start of an inspection and the unavailability of updated school self-evaluation forms.
But Ofsted said: "In general, it was found that the unannounced inspections did not present significant barriers to the inspection process."
The watchdog asked the 63 heads in the pilot who had two days notice inspections whether an unannounced visit would have been problematic. Ofsted said: "Their responses showed that no inspection would have been deferred."
But an NUT survey of 224 teachers has found that only 10 per cent supported the idea of no-notice inspections. Five days' notice was favoured by 49 per cent, two days' notice by 17 per cent, with 19 per cent saying half a term's notice would be beneficial.