At least two of a town's bridges which were damaged during Storm Dennis will need to be demolished.
Pontypridd was hit by severe flooding on 16 February as flood defences were overwhelmed during record rainfall.
Rhondda Cynon Taf council's leader said it will seek emergency powers from the Welsh Government to demolish Castle Inn Bridge and White Bridge, both of which are listed.
Andrew Morgan said the bridges could collapse if people walked on them.
Mr Morgan said White Bridge - also known as Berw Bridge - has "lost most of its support under one pier", meaning there was a risk the bridge could "give way" or "collapse"
Castle Inn Bridge provides a crossing between Treforest and Rhydyfelin, while the closure of White Bridge, also known as the Berw Road Bridge, has led to significant congestion in the town.
Mr Morgan said he was seeking emergency powers from ministers to demolish both bridges because they could collapse if people walked or drove over them.
If the council did not obtain emergency powers, it could take "many, many months" to do so, Mr Morgan explained.