The new zone now covers Dorset and the New Forest, Defra reported.
A further three new cases have also been found in Sussex, Essex and Norfolk, and existing protection zones have now been extended.
Separate protection zones covering East Anglia, parts of north-west London, Buckinghamshire and Hertfordshire have now been merged and extended.
All the new cases were discovered as part of the restrictions on farmers moving livestock out of the zones.
The Dorset case also means that parts of Wales now fall under the protection zone for the first time, the Welsh Assembly has confirmed.
For the first time, parts of Wales are now within 150km of a confirmed case of Bluetongue disease.
The Welsh Assembly said it has outlined the implications of this development for farmers in Wales.
The Restricted Zone covers the counties of Monmouthshire, Torfaen, Caerphilly, Rhondda Cynon Taf, the Vale of Glamorgan, Bridgend, Neath Port Talbot, Cardiff, Blaenau Gwent and Merthyr Tydfil. A small area of Powys is also within the Zone.
The same restrictions apply in the Restricted Zone as apply in the Surveillance Zone, which covers a large part of South East England and the Midlands.
Minister for rural affairs, Elin Jones, said: "This is obviously unwelcome news for the farming industry in Wales, but it is not unexpected. I would remind everyone that the disease has not been found in Wales and that is how we want the situation to remain.
"We are working in close partnership with stakeholders in order to minimise the economic impact of this development and to keep Wales disease-free. We are in agreement that the current Restricted Zone does not, at this time, need to be extended further into Wales. The situation will be kept under constant review."
Chief veterinary officer for Wales, Dr Christianne Glossop, said: "I urge the farming industry to comply with movement restrictions as announced today. First each farmer needs to find out whether their own livestock are now within the newly defined Restricted Zone. They can do this by checking our website for detailed maps and information.
"It remains vitally important that farmers maintain vigilance for this disease and report any suspect cases to their local Animal Health Office immediately."
The Welsh Assembly Government has ordered 2.5million doses of the Bluetongue vaccine which will become available later this year. The vaccine will be permitted for use within the protection zone.