New South Wales Police are warning people to watch out for online travel scams after hundreds of Vietnamese students were sold fake air tickets through social media.

Key points: Up to 400 Australian students sold fake air tickets to Vietnam

Up to 400 Australian students sold fake air tickets to Vietnam Vietnamese woman charged

Vietnamese woman charged Police urging travellers to be cautious of suspiciously cheap travel deals

Police said at least 300 students in Sydney and Melbourne bought tickets to Vietnam through a Facebook page only to find out at check-in that their bookings had been cancelled.

"We believe that upwards of 300 to 400 students could possibly be victims of this scam," NSW Detective Superintendent Gavin Dengate told the ABC's Vietnamese Service.

According to a police statement, the total value of tickets involved is estimated to be in excess of $360,000.

A 24-year-old Vietnamese woman was arrested last week and charged with 10 counts of dishonestly obtaining financial advantage by deception.

Mr Dengate said the woman allegedly began the scam by selling legitimate airfares on Facebook.

"The person was smart in that they got a bit of notoriety, or got some positive remarks for actually doing the right thing to start with, but then has gone into this fraud in a way that's deceived all the students," he said.

Mr Dengate urged people, especially international students, to be cautious of businesses offering special deals.

"If you're unsure or if it looks too good a deal, there's probably some hidden traps," he said.

"Ring the Department of Fair Trading, or equivalent in whatever state you're in, to enquire about that business.

"And if you have any issues, make sure you take them up with firstly your education provider ... and if you think you're a victim of a fraud, certainly come and speak to the police."

The accused woman was granted conditional bail and is expected to appear at the Downing Centre Local Court on February 3.

'She used our trust to take advantage of us'

Jade Nguyen, a student living in Sydney for five years, said friends recommended that she book her ticket through the Facebook page because of the woman's reputation as "a reliable agent with pretty good airfares".

Ms Nguyen said she transferred $1,050 into the woman's bank account, but did not receive seat reservation information or an eTicket as promised.

She discovered the scam when several members of the Vietnamese Dynamic Students (VDS) Facebook page posted that they had been swindled and intended to report the woman to police.

"This brought everyone else who had an eTicket to check Vietnam Airlines' website about the true condition of their tickets," Ms Nguyen said.

"Almost [everyone] reported back that their tickets were invalid or cancelled, or the reference number and/or ticket number they got was under someone else's name.

"Everyone was in a panic ... found out that the Facebook page and her phone had been de-activated."

Ms Nguyen said the experience has made her feel distrust towards the Vietnamese community.

"I feel a loss of my trust to the Vietnamese (sic), especially the students because she was a student before but it turns out she used our trust to take advantage of us," she said.

A scanned copy of a letter from the NSW Police Force was posted on the VDS Facebook page, asking for people who may be "victims of this fraud" to contact police.