A group of strangers have combined to expose a Sydney man they claim scams foreign students and backpackers out of thousands by renting them properties he does not own.

Key points: One man claimed Mr Murphy rented a room in his house to five different people

One man claimed Mr Murphy rented a room in his house to five different people Another told the ABC Mr Murphy owed him $3,600

Another told the ABC Mr Murphy owed him $3,600 Mr Murphy said there was "no legal claim" against him and denied wrongdoing

Darby Thomas Murphy styles himself as a member of Sydney high society and claims to work at a prominent law firm.

An online dating profile bearing Mr Murphy's name and photo described him as "connected" and "blessed financially from a young age".

But the ABC has spoken to several people who claim Mr Murphy has ripped them off, with some allegations dating to 2017.

NSW Police confirmed the matter was the subject of "an ongoing investigation".

Mr Murphy did not respond to specific questions about the allegations against him, but told the ABC he had been the victim of "vile" online threats and had complained to police.

The law firm confirmed that Mr Murphy was not an employee.

NSW Fair Trade Commissioner Rose Webb said her organisation had regular complaints about property scams in Sydney; however, they often involved money being sent overseas.

Darby Thomas Murphy is now the subject of a police investigation. ( Supplied )

Business student Daniel Barbosa arrived in Sydney from Brazil in 2016 and claims he was scammed out of $3,600 while trying to find a rental.

Mr Barbosa rented a room in an apartment Mr Murphy claimed to own in Chippendale but soon became suspicious of his fresh-faced "landlord".

"When he showed me the place he would always use the back door or enter from the garage and not go through the front past the concierge," Mr Barbosa said.

Three weeks after he moved in, Mr Barbosa received an eviction notice from real estate agency Dragon Australia, on behalf of the unit's actual owner, who was not Mr Murphy.

"I couldn't believe it — he [Mr Murphy] told me he was the owner, he was polite and told he me often worked at a law firm," Mr Barbosa said.

"I've never seen someone with those capabilities, he was so believable."

The apartment Mr Barbosa and Mr Murphy shared was in this building. ( ABC News: Mridula Amin )

Mr Barbosa confronted Mr Murphy and claims he refused to return his $3,600 bond.

"I felt damaged. I was powerless — I was just a student looking for a place to live and that was a lot of money for me," Mr Barbosa said.

He went to the police, who told him to pursue civil action because it wasn't a criminal matter.

The NSW Civil and Administrative Tribunal ordered Mr Murphy to repay the money, but Mr Barbosa says he has not seen a cent.

Mr Murphy told the ABC Mr Barbosa "occupied a property I rented in late November 2017" and said their relationship broke down shortly after Mr Barbosa moved in.

He said Mr Barbosa had "no legal claim" against him.

'I was worried about my safety'

English teacher Ribat Zaman met Mr Murphy in May while looking for a new roommate at his Milson's Point apartment.

"We spoke mostly over the phone and he seemed normal. He sounded like a young professional," Mr Zaman said.

"He came and inspected the property and moved in soon after, he was nice."

Three weeks later, Mr Zaman claims Mr Murphy fell behind on his rent.

"I became suspicious when he stopped replying [to text messages], then I googled him and found all these scam warnings from others," Mr Zaman said.

One of the warnings was from Mr Barbosa, so Mr Zaman contacted him and discovered several people claiming to be victims.

"I was worried about my safety and I sent Darby a message telling him to leave and not contact me," Mr Zaman said.

"He was using my place as a base to scam others and I had no idea."

Mr Zaman claims several people came to his apartment, believing they had rented a room. ( ABC News: Selby Stewart )

That night there was a knock at Mr Zaman's door.

A young student had arrived to move in to the property.

He said he had transferred money to a man named "Thomas" and that he had already inspected the unit when Mr Zaman was out.

Over the next fortnight, Mr Zaman claimed another five people knocked on his door with similar stories.

One of those was marketing student Katika Unjitanusorn, who moved to Sydney from Thailand with her partner last year.

She found Mr Zaman's apartment for rent online and claims Mr Murphy showed her the room.

"I was excited because it was the first time I found somewhere [to live] all by myself and I thought I could practice English with him," Ms Unjitanusorn said.

Ms Unjitanusorn was initially pleased to find a room to rent, but things quickly turned sour. ( ABC News: Selby Stewart )

She claims she transferred $420 rent, but when the couple arrived at the apartment no-one was there, and Mr Murphy had stopped answering his phone.

They left a note under the door and received a call from Mr Zaman telling them they had been scammed.

"I'm not confident now, I don't trust people, how can I?" Ms Unjitanusorn said.

Commissioner Webb confirmed her organisation was investigating complaints made about Mr Murphy.

"It is possible that when the amount of money for each person affected is pretty small that we don't hear about it," she said.

She urged anyone with similar complaints to report the incident to NSW Fair Trade.

"Because the rental market is an important one in Sydney, if people are affected by scams, they need to come forward," Commissioner Webb said.