Measuring and reporting minimum distance between lines

I have the following problem: Customers give me files to be laser cut. The laser cutter beam is 0.3mm wide. I need to be able to run through the entire drawing and highlight any lines that are closer to one another than an inputted value i.e. 1mm or 0.5 mm or whatever. I am having to do this manually at the moment and it is a serious pain. Is there a way to do this or has anybody done so?

Hi Adrian,

My first thought:
How about an offset bothsides and check for intersections?