Actually the crest is from Šentjur region, not Žalec. Red Žalec crest wasn't issued anymore after 2008, so red crest is on some 2004-2008 style plates and on old ones without euroband. Current Žalec crest is green one ;)
DutchPlateSpotter Thanks for the info! They look alike a lot so it was a hard one to distinguish. Are there any other crests that are rare like that?
Only Žalec has this crest change after 2008 but Slovenske Konjice and Šentjur crest look very much the same so when spotting any of those be careful when putting which one is ;)