Police have seen an alarming rise in the number of scams involving fake ads targeting grey nomads on online and print classifieds such as Gumtree.

Australia's travelling retirees - or grey nomads - are being scammed.Credit:Michele Mossop

They said scam artists are posting ads for machinery and recreational vehicles with eye-catching low prices and a phone number.

When an interested buyer calls, the scammer does not pick up but replies with a text message saying they can't talk on the phone.

Once they establish the caller is a genuine buyer, they usually direct the conversation to email to start price negotiations.

"Once a price is agreed, the scammer requests a considerable payment (up to 50 per cent) upfront by electronic transfer, then provide instructions to contact a freight company to arrange delivery and make final payment," NSW Police said in a public warning.

"It is understood that the freight company contact details provided by the scammer defer to another scammer, who takes a final payment before providing a fraudulent tracking number."

The goods never arrive and like with most scams, it's usually impossible to get any of the money back.

Con artists have used classified scams to fleece Australians out of nearly $2.2 million so far this year, according to the Australian Competition and Consumer Commission's (ACCC) Scamwatch.

In November alone, they snatched more than $230,000 from about 114 victims.

The ACCC urged people browsing classifieds to look out for warning signs, especially low prices that are too good to be true and sellers who say they're away and insist on early payment.

"When you show interest in the item, the scammer may claim that they are travelling or have moved overseas and that an agent will deliver the goods following receipt of payment," it said.

"Following payment you may receive a fake email receipt claiming to be from the websites secure payment provider, however, you wont receive the goods and will not be able to contact the seller."

The ACCC said genuine sellers were at risk of being scammed too.

"Scammers may make up stories such as needing your help to pay an agent or third party for upfront costs like transportation or insurance," it said.

"They may promise you reimbursement for these costs [but] you will lose the money."

In relation to the fake ads targeting the grey nomads, police said investigations showed these scams also involved identity takeovers, phishing, and mobile phone porting, which helps scammers hide their identity.

"Detectives from the Financial Crimes Squad have commenced an investigation and are urging the public to be vigilant when purchasing items through online or newspaper classifieds," it said.

The ACCC has warned Australians to also watch out for increasingly sophisticated "holiday season" scams such as online shopping scams, travel scams and parcel delivery scams, in which they ask you to print off a label, do a survey, claim a prize, or view the status of your delivery by clicking on a link in order to get them to download malware.

ACCC deputy chairwoman Delia Rickard said the best way to avoid the traps was to be sceptical and do research.

"Be sceptical about an online store you havent used before," she said. "Do some research to see if theyre legitimate and dont be fooled by big discounts."