The council fears the number of cases at the site will continue to rise before infection control measures start to take effect.
Testing has confirmed a COVID-19 outbreak at a caravan park in Shropshire with 21 new cases.
The individuals were asked to self-isolate for at least seven days from the time they started displaying coronavirus symptoms or from when they received their positive result.
However, the council fears the number of cases at the site will continue to rise before infection control measures start to take effect.
All residents at the caravan park, which is in the town of Craven Arms, will be asked to self-isolate with their household for 14 days if they have come into contact with one of the positive cases.
A testing centre has now been set up on a nearby business park and everyone living on site has been offered a test.
The centre will be open for the next two weeks between 10.30am and 3.30pm, and those living nearby can book a test online via NHS Test and Trace, or by ringing 119.
A playground close to the caravan park has also been closed in a bid to reduce social contact and the risk of transmission.
Councillor David Evans said: “Our priority is to protect the health and wellbeing of our local residents.
“I’ve been in Craven Arms to talk to residents and businesses to answer any questions and reassure them that the risk to the general public is low.”
He added: “I would like to thank members of the community for their own ongoing support and co-operation.
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“We continue to rely on everyone at the site playing their part, and want to encourage the residents to continue to self-isolate and take all the necessary precautions.
“This is the only way we can help stop the spread of the virus.”
Shropshire Council said staff had been providing residents with information on how to prevent the spread of the virus, its symptoms and what to do if they are feeling unwell.
It said it had also been distributing personal protective equipment, hand sanitiser, cleaning products and other supplies to residents.