The Australian Competition and Consumer Commission received more than 4100 reports of dating and romance scams last year.

Of the reported cases, just 25 per cent amounted to the $25 million-plus losses. The figure is the largest amount of money lost to any type of scam, and $3 million greater than the same reports of 2015.

"This is devastating. I've talked to enough victims to know they really do destitute themselves," said ACCC deputy chair Delia Rickard.

"Sending money, mortgaging their houses, they do whatever they can for the so-called love of their lives. And when they do come to the realisation it is a scammer, [they experience] emotional and financial devastation."

Consumer reports lodged with the ACCC's Scamwatch Service revealed that Facebook had become an increasingly popular channel used by romance scammers, with people aged 45 and over the most likely to be affected.

Internet (31 per cent), email (18 per cent), mobile apps (6 per cent) and other non-specified methods (12 per cent) were other common delivery methods used by scammers.

While women and men were fairly equally represented in the reports of romance scams (45 and 43 per cent respectively), women suffered much greater financial losses, to the tune of $11 million, compared with $7 million lost by men.

Ms Rickard said the growth in the use of social media was believed to be responsible for last year's increase in losses, which were likely just the "tip of the iceberg".

"Up until 2015, people mainly met scammers on dating sites, where there are only so many users. Now the main way scammers connect with people is on social media, targeting older people who may be less experienced and savvy," she said.

"Scammers create very believable profiles, including stealing the identities of real, trusted people such as military personnel, aid workers or professionals working abroad. If you meet someone who seems too good to be true, do some research ..."

In 2014, former Australian Idol winner Casey Donovan revealed that a six-year relationship she began with a man online was a hoax.

Among Scamwatch's reported cases last year, the ACCC received more than 442 relating to blackmail.

In such cases, scammers had threatened to send intimate photographs or webcam footage to a victim's family and friends via their Facebook friend list if they did not receive a payment. At least 64 of these cases reported financial losses.

To prevent such threats, the ACCC recommends that consumers avoid sending intimate videos or photos via the internet and keep their Facebook friend list set to private.

"We are doing a lot of work with intermediaries such as the banks and Facebook, to try to have them play a greater role in stopping scammers," Ms Rickard said.

"Some banks, and Western Union, are getting good at identifying when someone may be sending money to a scammer, by contacting them and trying to convince them not to."

Ms Rickard said Valentine's Day was a timely reminder of the need for consumers to be "on their guard" in what was a "cat and mouse game".

"Romance scammers are getting increasingly manipulative so, if you are going online this Valentine's Day to look for love, it's absolutely vital that you're able to recognise the warning signs." ​

In 2015, a Perth woman lost $300,000 in a romance scam after falling in love with what was a fake Facebook profile, to which several Australian women also fell victim.

It is believed most scammers are based overseas.

Scamwatch tips this Valentine's Day:

• Never send funds or your financial details to someone you have met online. Look out for requests for money orders, wire transfers or international funds transfer.
• Run a Google Image search to check the authenticity of any photos provided.
• Take care if you have moved communication away from a dating website, as scammers prefer to correspond through phone or private emails to avoid detection.
• Never share intimate photos or use webcams in an intimate setting, as you may become a victim of blackmail attempts.