I'm not familiar with what are considered "standard" metric size increments, but 44 mm is within typical precision of a 1-3/4" hole, which is a common US size and probably close enough for this purpose. You can get hole punches of this general style:
There are also gasket punches like this:
Image courtesy McMaster-Carr
That picture is from an expensive tool, but you can get inexpensive sets of similar style hollow punches containing a range of sizes. A common configuration looks like this:
This picture happens to be an expensive set that actually includes a 44 mm size, but places like Harbor Freight have inexpensive versions. These often include a centering pin that is removable.
Just the cutting dies are often available in sets sold as leather punches, like:
The set in this picture happens to be an inexpensive metric set that includes 45 mm cutter, which might be close enough.
You can make your own similar dies to a precise size by cutting up something like a steel food can, adjusting the diameter, soldering it, and then cleaning up and edging the cutting surface. People sometimes make fancy shapes this way for custom clay or cookie cutters.