Brisbane City Council says it is unlikely to recoup more than $450,000 it lost to scammers through phoney invoices over the past month.

Lord Mayor Graham Quirk said nine payments had been made to scammers since July 13.

"I became aware of this on Friday, the CEO became aware of it late on Thursday," he said.

"It's something I'm pretty angry about, it's a case of just over $450,000 that ratepayers have been robbed of.

"Through what appears to be a sophisticated and targeted scam."

Councillor Quirk said the scammers assumed the identity of a company and provided fake invoices and email addresses.

"They were payments that should've gone to a professional services provider but have gone to a scam account which was set up through a process which the scammers used," he said.

Cr Quirk said the fraud was being investigated.

"I've called in Deloitte to get them to do an investigation," he said.

"I'll be making the results of that investigation public."

Fraud a 'pretty sick feeling'

Cr Quirk said Deloitte would take about a month to carry out the investigation, and they would look at council's financial services and payment operations.

"Other entities like the Queensland Audit Office and the Queensland Police Service and even the CCC at this stage are engaged," he said.

"Scammers are fraudsters and they have their own sophisticated system.

"I'm hoping obviously that we get money back for ratepayers but just knowing the way these scammers work, I'm not holding out a lot of hope."

Councillor Quirk said many organisations suffer financial losses through scams.

"It's a pretty sick feeling. I just don't want to see a situation where ratepayers are being ripped off in this way," he said.

"If we can find those responsible for this, and I'm hoping that police inquiries will lead to that, then I hope that the full force of the law will be upon them."