The movement is thought to have started last week when Birmingham Council allegedly removed around 200 England flags from lampposts on safety grounds, prompting residents to paint crosses on several roundabouts in the city.
Many of the flags had initially been displayed as part of protests over the use of hotels to house asylum seekers in the city.
Councillor Hannah Young, cabinet member for highways and transport at North Somerset Council, said: “We understand how important national symbols are to many people and North Somerset Council is proud to fly the Union Flag from locations including the Town Hall in Weston-super-Mare.
“However, this pride should be shown in ways that are respectful and safe. We are aware of a small number of incidents where roundabouts and zebra crossings have been damaged or painted over.
“We urge people not to paint symbols over road markings as it can have an impact on visibility, distract drivers and increase the risk of accident for both road users and pedestrians.
“Road markings are strictly regulated for safety reasons and it is a criminal offence to deface them under the Highways Act 1980.”
She added that the council is working closely with partners, including Avon and Somerset Police, to tackle this issue and will investigate where appropriate.
Anyone who sees any damage to highways is urged to report it using the form on North Somerset Council’s website at www.n-somerset.gov.uk/do-it-online/report-or-request-services.
“Where flags and other notices have been attached to the highway without permission, they pose a similar risk as they can fall and obstruct the view of drivers, therefore they will also be removed,” Cllr Young added.
“The council is committed to supporting civic pride, but this must be in ways that are within the law.
“The cleaning of defaced road markings and the removal of unauthorised banners costs money which takes valuable resources away from delivering other, much valued council services.”