The consumer watchdog is joining forces with government anti-money laundering agents to crack down on internet love scams.

The Australian Transactions Reports and Analysis Centre will alert the Australian Competition and Consumer Commission when suspicious cross-border money movements suggest somebody is being scammed.

The ACCC will then send letters to suspected victims with warnings to stop sending money, and in future might follow up with phone calls.

Love scams are the most costly in existence, often targeting the lonely and the elderly.

Already this year the ACCC has found 43 people who have lost upwards of $100,000 each.

In some cases, victims have sent more than $1 million overseas over several years, said ACCC deputy chair Delia Rickard.

In others, victims have continued to send money even after having been warned that they were being scammed.

"People often mortgage their home, they borrow from friends and relatives. There are really tragic stories," Ms Rickard said.

Scammers tend to approach victims on dating sites and social media and profess their love very quickly.

They'll then spend months and years building trust before spinning a sob story and requesting large amounts of cash.