"We look forward to receiving payment of your invoice," the letter ended.
Mrs Fraser-Davies said she sent a small payment of $100 plus GST in response as this was a fee she found "more reasonable" than the actual fee of just under $600.
"I really want to get on top of all of this rubbish and I really probably have to thank MPI for honing my battle skills so that when I had to direct them to keeping myself alive it was a success," she said.
"What MPI was trying to do was make regulations simple and efficient by clobbering everyone with the same fee.
"I think they need to know that when we have lots of European visitors, and we do, they are honestly shocked that New Zealand, as the dairy centre of the world probably, has very few artisan cheese makers.
"I always say that's because MPI are doing their very best to frighten us all off.
The tourist potential for people to come explore the little places in New Zealand is enormous; to stop somewhere, be able to buy some local cheese and enjoy it, go to farmers' markets, and all those sorts of things."
Mrs Fraser-Davies said she is on the mend and has gone back to making cheese at Cwmglyn with some extra help.
"At my age, I'm quite happy for other people to benefit from my experience, and if we can get a regime set up that makes it easier for younger people to be able to make good cheese it will be well worth the battle."