Green cover on set-aside land must normally be cut between 15 July and 15 August or destroyed between 15 July and 31 August.
But the Rural Payments Agency said farmers could delay cutting in view of the heatwave.
Farmers wishing to make use of this derogation should telephone, e-mail or write to RPA Customer Service Centre with field reference numbers and an explanation of the fire risk – such as flinty soils, proximity to hedges or nearby standing crops.
The RPA said farmers may consider that the derogation has been granted unless they were told otherwise.
Requests have also been received to allow grazing on set-aside land. This can only be permitted with EU approval and an urgent case is being submitted to the European Commission.