The UK Government's flood warning system has posted the lower, flood alert risk for the Severn Vyrnwy Confluence from the Welsh border to Shrawardine north of Shrewsbury.
It says river levels remain high as a result of recent heavy rainfall.
"We expect flooding to affect low lying land and roads adjacent to the river from the Welsh border at Llawnt to Shrawardine near Shrewsbury," a spokesperson said.
"Other locations that may be affected include Llanymynech, Maesbrook and Melverley. Minor roads between Maesbrook, Melverley and Pentre maybe flooded."
Further rainfall is forecast for the rest of the week and river levels are expected to remain elevated.
"Please avoid using low lying footpaths near local watercourses and plan driving routes to avoid low lying roads near rivers, which may be flooded," the alert says.
Natural Resources Wales has a flood alert in place for the River Severn across the Welsh border.
It says roads close to Meifod Bridge, the B4393 near Llansantffraid Bridge and the B4398 at New Bridge Llanymynech could be affected by the rising levels and the situation will be continually monitored.
There are also alerts for the River Dyfi in mid Wales and large parts of the Gwynedd coast and Lleyn Peninsula in north Wales.