Denbighshire Countryside Service is calling on all dog owners to make sure their animals are kept on a lead when they walk in the open countryside.
In recent weeks, there have been incidents reported in the local press and on social media about dogs attacking livestock.
The service has dealt with a number of dogs reported missing on Moel Famau after being let loose and disappearing into the heather moorland, sometimes for lengthy periods of time.
David Shiel, Countryside Officer, said: "Although Moel Famau is a Country Park enjoyed by residents and visitors it is still farmland and grazed by sheep and cattle throughout the year. .... We don't want to discourage walkers with dogs.
"All we ask is that the dogs are kept on leads, for their own safety and to offer peace of mind to their owners. There are also plenty of other areas such as forestry in the vicinity where dogs can be let off their leads safely.
"We also want to ensure that there's the right mix of people using the countryside for enjoyment, as well as others using the countryside to carry out a living."