The scammers, who masquerade as legitimate property owners, try to fleece their victims of thousands of dollars by asking them to make deposits and rental advances for properties advertised online.

Student Rachael Clancy was asked to send $2330 via Western Union to a couple who said they owned an apartment on Honeysuckle Drive, Newcastle.

Ms Clancy, 21, saw the furnished two-bedroom apartment advertised on legitimate website gumtree.com.au for $740 a month.

After making an online inquiry, she was contacted by a man who said he and his wife were seeking someone to occupy the apartment while they were overseas working for a Christian aid organisation.

"They said they didn't need the money, they were just looking for someone to take care of their place," Ms Clancy said.

She said she was asked to complete an online application form, which sought details including her religion and occupation.

"I was drawn in by the rent," Ms Clancy said. "I think that's what they are targeting, the younger people who go, 'That's cheap.' "

After being advised her application had been accepted, Ms Clancy was asked to transfer $2330 via Western Union.

The scammers promised to send the apartment keys and documents via DHL courier service once payment was received.

Before sending the money, Ms Clancy contacted DHL to confirm her tracking number and was advised the frauds had told other people they were using the courier service.

"DHL told me in the last month they have had the exact same story and heaps of people have lost their money," she said.

Further investigation showed a legitimate real estate agent was advertising the Honeysuckle apartment.

The fake advertisement has been withdrawn from the website and police are investigating the case.

A spokesman for gumtree.com said most transactions among Gumtree users were trouble-free.

"Whilst Gumtree doesn't undertake user verification, it takes any report of fraud very seriously and works with the authorities and our community to remove any questionable listings to keep the Gumtree site clean," the spokesman said.

A DHL spokeswoman urged anyone who doubted the authenticity of a notification message to contact DHL Customer Service on 13 14 06 for verification.

"DHL takes customer relationships seriously but cannot take responsibility for unauthorised actions of third parties," the spokeswoman said.