Australians planning to go to a holiday rendezvous ought to take extra precautions in their online booking activities as the Australian Competition and Consumer Commission (ACCC) on Thursday disclosed at least some $250,000 worth in Internet scams have been lost in 2013 alone.

Scammers have apparently been able to penetrate into the Web sites of legitimate rental and travel-related companies, accessing inquiries sent through email by interested consumers. They will then assume the identity of a property owner and work to arrange bogus bookings.

"While you're making holiday plans, scammers are plotting to steal your hard-earned dollars," Delia Rickard, ACCC Deputy Chair, said.

This year alone, the agency received more than 100 travel-related complaints, ranging from fake rental listings, bogus holiday vouchers and hackers as the most common issues.

"Our most commonly reported travel scam comes from holidaymakers finding that discount accommodation vouchers they paid for don't arrive, are fakes or simply can't be used as promised," Ms Rickard said.

She urged Australians to always counter check every bit of information they receive or was able to hold regarding their travel plans.

"Before booking your holiday, do your homework by contacting the company directly using details that you have sourced independently through the phone book or an online search. Often scammers have no arrangements with the accommodation providers to offer discount stays," Ms Rickard said.

"Don't trust the legitimacy of an ad just because it appears in a reputable newspaper or online classifieds website as scammers often use these. If you receive an email out of the blue from a stranger offering a great holiday deal, delete it and do not click on any links or open attachments."

Keeping your computer security up to date with anti-virus and anti-spyware software and a good firewall is also a must, she said.

"If you think you have provided your financial details or sent money to a scammer, contact your financial institution immediately."