Under the options being considered, external, inpatient wards would be retained in Brecon and Newtown, with Llandrindod Wells potentially remaining open under the three-site model.
Beds could be lost at Welshpool, Machynlleth, Ystradgynlais and Llanidloes, as well as Llandrindod Wells under the two-site option.
Changes being considered are part of Powys Teaching Health Board’s Better Together, external programme with the health board saying that action is needed to “make services safe and sustainable” as demand for care increases.
Changes are needed to respond to “major challenges facing health services” at a time of rising demand, when people are living longer often with many long-term health conditions, it said.
Powys also has one of the oldest populations in Wales, with more than a quarter of the population over 65.
It is also becoming increasingly difficult for the health board to recruit and retain staff with the skills it needs, while delivering services in a large, rural county is also challenging.
According to the health board’s proposals would mean longer journeys for some patients with the average travel time to inpatient care rising from about 12 minutes to 24 minutes.
For people living furthest from hospitals, average journey times would be more than 45 minutes each way.
Dr Carl Cooper, chair of Powys Teaching Health Board, said confirmation of the consultation marked the “beginning of a conversation, not the end of one”.
“No outcome has been predetermined,” he said.
“The recommendations approved today have been informed by feedback from thousands of patients, residents, NHS staff and partner organisations over the last two years.
“We will need to understand the evidence, experiences, concerns and alternatives raised during consultation and give them conscientious consideration in public before any final decision can be made.”