Louise, there are fillers made to take care of this, available in various colors.
Check with a local laminate retailer about getting what you need. It will help if you know the brand laminate and pattern name; then you can get exactly the color made for this surface. If you're unsure, get sample chips from the retailer to compare with your top, and use the filler for one which most closely matches yours. These can also be blended, like paints, to come up with patterns or different shades.