A kind-hearted stranger has paid a parking fine for a mother who had spent days in hospital with her sick child.

Now an image of the note left by the well-wisher known as Laura has gone viral, shared more than 7000 times since it was posted on the Canberra Mums Facebook page.

The incident came to light after it was posted on social media by the grateful parent.

"I saw your car had a parking ticket on it," the note left on the mother's car read.

"I'm sure whatever you are going through at hospital is tough enough so I paid for you. Hope things get better."

The anonymous mother expressed her thanks by sharing the note on Facebook.

"Over the past few days I have been in hospital with my 9 week old son," her message read.

"We were discharged today and as I walked to my car I noticed that I had a parking ticket. After those days in hospital, a parking ticket was one more thing that I didn't need.

"Well to my surprise, when I opened the envelope there was a note from a lovely lady named Laura.