Yeah, it's the heavy duty pet mesh. Cut with scissors. It really needs to be attached to some sort of frame to keep it from shifting, being dug out of the way, or edges chewed on. I made mine from 8 ft plastic j trim edging. It has about a 1/16" channel. I cut the edging pieces with heavy duty scissors, then punched holes using a leather punch so I could secure the edging onto the screen with zip ties. I had thought about just using a normal window screen frame, but it would have been more expensive than what I used. If you are only doing a single screen, it might not be worth it to you as you probably have to buy a whole roll. I got a 7 ft. roll at walmart for $13. I had several screens to make, so it was worth it to me, but might not be for you if you only need one screen. If you could buy by the foot, then it might be worth it. If you really want to give it a try, I can post some pictures of the supplies I used and how to assemble.
If you want to try something a bit more simple, the plastic cross stitch canvas is cheap and easy to fit. All you have to do is cut to size with scissors. And it's not too rough on bunny feet. I gave them a try and still use one on a litter box, but ended up making the pet mesh screens because some bunnies decided it would be fun to chew the cross stitch canvas ones
So that could be an issue for you, but you wouldn't be out much to try it even if it didn't work. I found I liked the 5 count canvas best, with the bigger holes for good urine drainage, and you want the stiffer canvas. This is what I used.
http://www.joann.com/plastic-canvas-13-1-4inx22in-clear/1971258.html
ETA: Yikes!!! Just looked the pet mesh up on bunnings, and it's quite expensive. If you can find the cross stitch canvas, that might be the best thing to try. Then if it doesn't work out, the welded wire screen, though I'd probably layer hay over it to make it soft for little bunny feets
