Council recreation manager Erik van der Spek said the council was informed of the graffiti at 8am.
The graffiti, which read ''F*** 1080'' for southbound drivers on State Highway 1 and ''Ban 1080'' for northbound drivers, appeared to be denouncing the Department of Conservation's use of 1080 as pest control.
Anti-1080 protests have been on the rise recently. Over the weekend, anti-1080 protesters locked Auckland Council staff members in the Hunua Ranges Regional Park where a 1080 drop has commenced.