A range of new measures will come into force on Tuesday at 6pm in a bid to reduce the number of new coronavirus infections.
The new restrictions will apply to everyone living within the Caerphilly County Borough Council area.
They are being introduced following a rapid increase in the number of confirmed cases in coronavirus, which have been linked to clusters of people meeting indoors, not following social distancing guidelines in the borough and summer holidays overseas.
They will be kept under regular review but if cases do not fall, the Welsh Government, working with Caerphilly Council and Public Health Wales, will consider further measures.
Health Minister Vaughan Gething said:
"We have seen a significant rise in cases in Caerphilly borough over a very short space of time, which are linked to holiday travel abroad and people socialising indoors and not following social distancing guidelines.
"A lot of these cases are in younger people and thankfully, at the moment, most of these are mild. But coronavirus is now circulating in the community and it’s only a matter of time before we start to see more serious cases, which need hospital treatment.
"We need the help of everyone in Caerphilly borough to prevent the increasing and onward spread of coronavirus. We can only bring this local outbreak under control if everyone pulls together and follows these new steps.
"If we do not see cases falling, we may need to take further steps to bring this local outbreak under control."
In the last seven days there have been 133 new cases confirmed, equivalent to a rate of 55.4 cases per 100,000 population – the highest rate in Wales and one of the highest in the UK. It is expected case numbers will continue to rise.
Community testing was introduced in Caerphilly at the weekend. On Saturday, some 450 people were tested and 19 were positive – a positivity rate of 4% – indicating the virus is circulating in the community. A similar number of people were tested on Sunday and the results are expected shortly.
All the new restrictions will come into force at 6pm on Tuesday.
The travel restrictions will mean people cannot enter or leave Caerphilly County Borough Council area without a reasonable excuse – this includes work, if they are unable to work from home, or making a compassionate visit to a loved one or to give care.
People will only be able to meet others outdoors for the time being as indoor meetings and gatherings will be restricted. However, care visits will be able to go ahead.
Caerphilly Council has already introduced some measures in response to the increase in cases – it has temporarily suspended visiting to care homes in the borough and is introducing weekly testing for care home staff.
Councillor Philippa Marsden, leader of Caerphilly Council, said:
“We need to create a break in the cycle of infection we are seeing in Caerphilly borough at the moment and unfortunately that means introducing new, tougher restrictions.
“I would urge everyone living in the area to follow these new measures; to follow the social distancing guidelines and to wash their hands regularly. If we all work together, we can bring this outbreak under control and reduce cases of the virus.”
The new measures will be kept under regular review and enforcement of the new restrictions will be undertaken by the local authority and by the police.