Dumfries and Galloway Council have confirmed that they were not responsible for the lines which have appeared across the entrance to an alleyway between W Glendinning & Son and Harper, Robertson and Shannon.
A spokesman for the local authority said: “We are aware of the issue and will be removing the self-painted lines.”
And confirming work to more clearly establish parking bays for vehicles, he added: “The ‘H-Box’ lines in that area of the High Street will also be refreshed.
“We’ve made contact with Police Scotland to see if they have any evidence of who the street artist culprit is.”
Police Scotland say the actions might be classed as vandalism.
And a spokesman said: “If someone has taken it upon themselves then there is obviously no legal foundations to such lines on roads.”
But he added: “If you park across that close, irrespective of whether there are lines there, then you’re causing an obstruction because someone cannot get in or out that close — so that’s actually an offensive itself.”