A Melbourne dog has been handed to a vet in mysterious circumstances three weeks after she went missing.

Owner James Fitzgerald previously told 9news.com.au that 11-month-old King Charles spaniel Ethel was taken from outside his girlfriend Monica van Dam’s Easey Street property on January 31.

A neighbour’s security footage showed an unidentified man leading the dog away from the property at 10.17am.

Mr Fitzgerald was concerned for Ethel’s wellbeing because she suffered multiple health conditions.

Ms van Dam with her beloved dog. (James Fitzgerald)

He and his girlfriend initially had little luck tracking her down, with no leads from the dog’s microchip.

However, earlier this week, Ethel’s microchip was scanned at a vet about 25km away and Mr Fitzgerald and Ms van Dam received confirmation she was alive and well.

“After a conversation between Central Animal Records, the Department of Economic Development, Jobs, Transport & Resources, the police, the treating vet and the person who was in possession of Ethel, she was finally returned,” Mr Fitzgerald told 9news.com.au.

“We drove out to the St Albans vet in the evening and Ethel was so excited to see us that she almost passed out.”

Ethel was taken from outside the Easey Street property on January 31.

Despite having lost a significant amount of hair, Mr Fitzgerald said Ethel was otherwise in good spirits.

He said that he and Ms van Dam are relieved to have their beloved pet home and were keen to get “back on with our lives”.

“We are going to cherish every moment with her and perhaps throw her a party next week for her (first) birthday,” Ms van Dam added.

Ethel with owner James Fitzgerald. (James Fitzgerald)

Mr Fitzgerald believes Ethel may have been sold to the new owner via Gumtree and has advised the public to only purchase pets from reputable sources.

He also stressed the importance of microchipping animals and keeping the chip details up to date.