Police officers could become exhausted because they cannot book any more leave this year as a result of the imminent badger cull, it has been claimed.
Gloucestershire Police said it would not be authorising any further time off before January in anticipation of expected clashes between farmers, marksmen and animal rights activists.
But the Gloucestershire Police Federation said it was concerned officers could become tired, which could lead to mistakes and accidents.
Chairman Tracy De Young told the Gloucestershire Echo: "Officers are becoming increasingly fatigued due to the lack of rest.
"We are concerned that as fatigue takes hold, mistakes will be made and accidents will occur.
"Officers will continue to do their very best for the communities we serve, but I am afraid that this will lead to a reduced service, a dip in performance and could lead to increased levels of complaints."
She added that officers had also been unable to book leave this summer due to London 2012 and there was already an increase in sickness.
Farmers in west Gloucestershire have been granted the first licence for a pilot cull of badgers designed to tackle TB in cattle.
The cull is due to begin shortly, but the exact area has not been made public amid concerns over protests.
Gloucestershire Police said it would need officers to meet the "increased demands" they could face during the cull.
The force said in a statement: "We will not be authorising any further annual leave or time off requests for police officers, except in exceptional circumstances, until the New Year.
"This is regrettable, but is standard practice when planning for events which may place increased demands on our resources.
"Any leave already booked will be honoured.
"The situation will be kept constantly under review."