The Powys Association of Voluntary Organisations has urged people to be aware that some locations will still ask people to wear masks.
It comes as restrictions have been lifted by the Welsh Government.
PAVO Health Promotions Facilitator, Gareth Ratcliffe, said: "From today – we would kindly ask patients presenting with any respiratory condition (even if testing negative on LFT) to continue to wear a face-covering when attending the surgery, this is both to protect them but also other vulnerable patients and the staff.
"Covid-19 is still affecting health teams and impacting services within our community and will continue to do so for the foreseeable future.
"We have small teams and losing members of staff who are infected with the virus and need to isolate in line with current regulations for health care staff, puts a strain on our teams to continue to deliver service to all of the community.
"Wearing of face masks continues to be under review at a local level, and although currently not a legal requirement we are very conscious of the un-contained spread of Covid-19 and would ask everyone to support us with this when requested."