Westpac Banking (ASX:WBC, NZE:WBC) on Friday warned its customers about a rising scam known as "romance baiting," where fraudsters pose as romantic partners or friends to lure victims into fake investment schemes.

Investment scams account for nearly 20% of all scam cases but almost 50% of financial losses, the bank said. Scammers often use fake ads on social media or establish relationships online before suggesting fraudulent investments, the company said in a statement.

Scammers creatively pose as romantic or platonic partners, offering investment advice while claiming no personal gain and spending weeks or even months to build trust before they initiate any "investment opportunity," the company added.

Signs of a potential scam include suggestions of unrealistic profits, using unsecured websites, exclusively online or phone-call communication, and asking to send money to access your supposed profits, added Ben Young, head of fraud prevention.

If suspicions arise, the bank said that customers must stop communication with the scammer, contact the bank, and report the scammer.