Bird flu protection measures imposed following the November outbreak of the disease have all been lifted.
The virus was confirmed at Redgrave Park farm
Restrictions on bird gatherings and movements of poultry and poultry meat within the zones affected have also been removed.
The Department of the Environment, Food and Rural Affairs (Defra) said the move followed advice that the disease was confined to two farms in Suffolk.
However, the cause of the outbreak is still unknown.
Acting chief veterinary officer Fred Landeg said there would be an ongoing investigation to find the source of the virus.
He said: "Although this marks the end of our active disease control measures in the affected area, we continue to investigate the source of the virus introduction, and expect to publish a final epidemiology report in the new year.
"Poultry keepers must endeavour to learn from this outbreak to prevent and manage similar situations in the future.
"All should regularly review their biosecurity measures to ensure they meet best practice and remain vigilant for signs of disease."
The final lifting of restrictions comes after the culling of thousands of birds on six premises in Norfolk and Suffolk following the discovery of the deadly virus at Redgrave Park farm on 13 November.
The second protection zone was set up around the nearby Hill Meadow farm, which shares its workforce with Redgrave Park, and to which the disease had spread.
Millions of birds worldwide have either died from the H5N1 strain or been killed to prevent the spread of the disease.