Public servants faced questions about the fraud during annual report hearings in the ACT Legislative Assembly on Friday, after it was revealed in The Canberra Times earlier this week.

The fraud involved a still unknown culprit submitting a false invoice to the taskforce, for an estimated $190,000 payment that was meant to go to a construction contractor, but instead was deposited into what police have called an "illegitimate" bank account.

But more than 12 months after the fraud was referred to police, and despite the ACT Policing investigation also trying to find the culprit through the federal police's international arm, the fraudster has not been located.

Opposition housing spokesman Mark Parton asked a series of questions about the fraud during the hearing, where planning director-general Ben Ponton said the scam appeared to have been executed by a "very sophisticated operator".

Mr Ponton said the scammer had used a recognised email address for a taskforce building contractor, including details such as the firm's own bank account and the authorised person's name, saying they had recently submitted an invoice, but asking to change their bank details.

He said the staff member had gone through the claim and it appeared legitimate, and so deposited the funds into the new bank account.

"Very soon fortunately after that, the actual person got in contact to ask where that payment was and we said we've made that payment and very quickly we were able to recover the monies and identified, as I recall, the bank account was at a bank in Melbourne airport," Mr Ponton said.

"The point is, it was quite sophisticated and whoever did this had the details of the directors of the company, they had their email addresses and were able to get an address that was essentially the same for all intents and purposes we were dealing with the identified the person."

Mr Ponton said within hours of contacting the relevant bank, the illegitimate account had been frozen and the funds returned to taxpayer coffers.

Mr Parton asked whether the police investigation had been completed or the culprit identified since, to which Mr Ponton said it was not for him to comment on the police's work.

But deputy director-general Geoffrey Rutledge said it was possibly not an Australian resident that set the scheme up, and if he were to speculate, it could be an overseas-based scam.

He also said he had talked to others around town about the scam, suggesting it was likely other capital works companies in the city may have also fallen victim to similar fraudulent activity.

But Mr Rutledge said the investigation and audit into the fraud was crystal clear it did not involve any territory public servants, or any evidence someone within the territory government had set it up to benefit from it.

Asked about the total amount of the fraud, Mr Ponton said he was not entirely sure of the exact sum, given it was a year ago, but he believed it was about $190,000, but he might need to check the detail.

He reiterated that all the monies were quickly recovered and said that we all needed to be vigilant.