Welsh Conservative MS Darren Millar has described YesCymru stickers that have been placed in public spaces as "littering and graffiti of the highest order."
Mr. Millar made the comments during a Senedd plenary session about the decision to emblazon an eight-storey Union Flag on the corner of a new UK government building in the centre of Caerdydd.
Mr. Millar said that Plaid Cymru MS Rhys ab Owen, who had raised the matter in the Senedd, "would not be raising such objections if this was Y Ddraig Goch that was going to be erected"
Mr. Millar, the MS for Gorllewin Clwyd, then asked the First Minister what action the Welsh Government was taking "to address the proliferation of Yes Cymru stickers around the length and breadth of Wales?"
He also described the stickers as an "affront to local communities" and "littering and graffiti of the highest order."
The First Minister said that "it's not a matter for the Welsh Government."