DOG owners are being warned to keep their pets under control in lambing season or they could face legal action.

A new ruling under the Countryside and Rights of Way Act 2000 states that dogs legally need to be kept on their leads while on open access land.

It came into force on Monday, March 1 and if dog owners do not keep their pets under control they can be banned from using the land the offence was on for several days.

The ruling also states that if a dog disturbs the nest of a rare bird the pet's owner can be liable to a large fine.

Owners can also be fined under the Dogs (Protection of Livestock) Act 1953 if their pets are found to be worrying or chasing livestock.

Local farmers have raised the issue of dogs being kept on leads as a concern in the area as lambing season approaches.

PC Clare Mayes, Countrywatch liaison officer for Thirsk, said: "I would like to remind all dog walkers to ensure that their pets do remain on their leads where required.

"It is important that they remain obedient and under control at all times to ensure there is no potential for them to chase or worry sheep that may be in lamb.

"Livestock are an important part of farmers' livelihood and they would appreciate the public's assistance in protecting their animals at an important time of year for them."

The police have vowed to investigate any incidents of sheep worrying which are reported to them from across the region.

The National Farmers' Union (NFU) said farmers should seek advice before shooting dogs they think are worrying livestock.

Alastair Johnston, a livestock advisor for the NFU, said: "Most people keep their dogs under control but there are some who don't abide by the rules.

"Over the years we've had a number of incidents of dogs getting in amongst sheep and scaring them and it can cause damage to their welfare.

"We encourage farmers to put up signs asking people to keep dogs on a lead if sheep are present.

"If a dog causes damage to sheep then farmers may be able to claim compensation from the owners of the animal.

"We tell farmers to get control of the situation and find out what has happened and involve the police if needed before acting rashly."