Sustrans is advising cyclists and walkers to refrain from using rural sections of the National Cycle Network during the current foot and mouth outbreak.
John Grimshaw, Sustrans Director and Chief Engineer, said: "We are asking the public to heed government advice on this matter. Anyone in doubt about travelling in their locality should contact the Ministry of Agriculture Food and Fisheries. We have already been told that some stretches of the Coast to Coast (C2C) Route in Cumbria have been closed as has the route between Cossington and Bawdrip in Somerset."
Many of the National Cycle Network routes run through farmland and rural areas.
Sustrans guidance is echoed by the CTC (Cyclists Touring Club). It has urged cyclists to avoid countryside routes. It says mountain bikers should drop their offroad plans while road riders should think carefully when planning their routes.
Michael Breckon of the National Byway is hoping to launch his new tranche of northern routes soon but fears the foot and mouth outbreak will delay his plans.