Access to Main Street from Church Street and Goff Street in Roscommon town to the west of the Square has been opened to alleviate traffic while public realm works continue.
Motorists are experiencing long tailbacks on the Circular road as access the Square remains closed to traffic from both Castle Street and Lanesboro street.
This will continue while Phase 3 of the works progress until August.
While diversions will be in place, the local authority says pedestrian access to all premises in the town centre will be maintained throughout.
Daire Stevens from the Comfy Café on Main street says communication is key with businesses.