Dog owners will have to keep their four-legged friends on leads for half of the year when out for a walk on a section of Holkham beach where shore birds nest.
And slightly more of Wells beach will be off-limits completely to dogs in a bid to make life easier for seals.
Jake Fiennes, Holkham National Nature Reserve's director, said: “The Holkham National Nature Reserve must be one of the most amazing stretches of coastline in the UK.
"Visited by many, it is the responsibility of us all to ensure that these natural places remain rich and vibrant. We share these special places with a range of wonderful wildlife, so let us jointly protect it.”
Under the rules, dogs must be kept on leads on a 90-hectare section of beach around Holkham Gap between April 1 and August 31, and dog owners are advised to keep pets on leads in the 20 hectare area called Gun Hill on the beach's western edge during the same timeframe.
An area at Wells beach where dogs are already banned will be extended northwards to include a seal haul-out area. This area already covered four hectares and is increasing by around two hectares.
The reserve's total area accessible to the public, including pinewoods and sand dunes, is more than 650 hectares.
Mr Fiennes said Holkham Gap and Gun Hill were nesting grounds for little terns, oyster catchers and ringed plovers, all of which were in decline.
He said the changes were being made in partnership with West Norfolk District Council, whose habitat monitoring and mitigation fund helped to pay for a second beach warden for Holkham beach. He said more than 2,000 people had commented on the plans over a 12-week consultation.
Mr Fiennes added: "We're not banning dogs. We're trying to make sure it's a great place for wildlife and a great place for people to exercise their dogs.
"We also want it to be a great place for families to come and enjoy the beach without the worry of dogs.
"We are custodians of the landscape and we want to leave it for our children in a better condition than when we took it on."
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