A homeless man has made a desperate plea to find his missing pet rat after it was stolen from the street.

Pet owner Chris claims that his beloved rodent was nabbed from its home outside Footlocker on Pitt Street in Sydney last weekend.

'My pet rat Lucy was stolen on Saturday,' he wrote on a sign.

'Lucy is black and white with a bit of brown,'

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Pet owner Chris claims that his beloved rodent was nabbed from its home outside Footlocker on Pitt Street in Sydney last weekend

The homeless man has become a local identity in the city with numerous people on their way to work stop and pat the rat as it sat perched on its milk crate

The 59-year-old told Daily Mail Australia he had just gone to the bathroom across the road and when he returned, his pet was gone.

'I don't want to press charges against the person who stole Lucy. I just want her back.'

The homeless man has become a local identity in the city with numerous people on their way to work stopping to pat the rat as it sat perched on its milk crate.

'Almost everyday since I started my job in the city Chris & his pet rat Lucy have sat in the same spot, Chris chatting to passersby & Lucy happily munching, sleeping & looking on,' one distressed person said in a Facebook post.

'They are a feature of Sydney city life and I have always smiled when I see them & felt glad they had each other.'

Another person said: 'I've passed him so many times he's always been so friendly my son is always amazed that he has a pet ray that doesn't try and run away.'

A couple had gifted the rat to Chris when the rodent was only four-weeks-old.

'She was family. I would lean down to her and say, 'how are you?' and she would get up on her hind legs and give me a peck.

'She only bit me once, but that was because I was feeding pigeons out of my hand and I rubbed my mouth and she would've thought there was food on my lips or something,' he laughed.

While lettuce and corn was the pet's favourite food, Chris admitted Lucy had her weaknesses.

'She loved cakes. I would also let her drink a bit of coke mixed with water or coffee as a treat.'

And just as locals shared in the good times, there were also several down moments.

Only six weeks ago, a tumour was removed from the rat, though thankfully the pet made a full recovery.

And now news of the alleged theft has left many heartbroken.

'I was genuinely distressed to pass by today & see Chris without Lucy and for him to tell me that on Saturday some heartless person had whisked her away,' a person said on Facebook.

Another person commented: 'Taking a homeless person's loved pet - seriously, what a really low act.'

Moments later, the rat is found napping near its food after a big lunch

Chris' plea for help has been shared to Facebook and one post has been shared close to 10,000 times in a desperate bid to locate the rat

A photo of Chris shows the homeless man sullenly sitting next to his crate. Over the top is a blue blanket, where the rat normally rests on. Attached to the bare crate, is the sign imploring for help to find his pet.

Concerned residents took to social media to lament the close friendship the pair had shared over the years.

'His rat was one comfort he did have in life, which is why everyone is so sad for him,' one person said.

Other locals have taken to social media to share their fond memories with the rodent.

In one photo, a woman poses with Chris while Lucy playfully crawls on her scarf.

Another photo shows the pet perched on the crate, next to its bowl of water with chewed lettuce and corn scraps nearby.

Moments later, the rat is found napping near its food after a big lunch.

Chris' plea for help has been shared to Facebook and one post has been shared close to 10,000 times in a desperate bid to locate the rat.

'I don't know why this had to happen to me,' Chris said.

'I haven't done anything bad to deserve this - I was brought up to respect people.'

He said the disappearance had left him heartbroken and wondering if he was to blame.

'Everyday this week, I've been thinking should I have waited a little longer before I went to the bathroom. But I always go to the bathroom and she's always there when I get back. I'm scared that if I leave this place, she'll come back and I won't be there.'

A NSW Police spokesperson said officers were investigating the incident.