Businesses lost a total of £92.7 million in 2018 to scammers posing as their suppliers, according to a report from UK Finance.
Invoice scams are a type of fraud in which criminals trick businesses into transferring money by posing as legitimate payees, such as a regular supplier.
Last year, businesses were involved in 3,280 such cases, each with an average loss of £28,000.
Despite this risk, a separate survey of 1,500 firms in the UK found that 43% were unaware of invoice fraud.
Only 14% of sole traders said they had taken steps to protect themselves from these kinds of scams, compared to 47% of small businesses.
Katy Worobec, managing director of economic crime at UK Finance, said:
"The gangs behind this type of fraud are increasingly sophisticated and will often get hold of details that allow them to pose convincingly as regular suppliers.
"If someone contacts you asking for a supplier's bank account details to be changed, always verify with that supplier separately on the phone or in person, using the contact details you have on file."
Contact Action Fraud if you think you may have been a victim of a scam.