An independent review of the internet provider's proposal, released under Freedom of Information laws, also revealed the government was warned of technical challenges to providing free Wi-Fi on ACTION buses.

The $3.1 million network will be the largest free public Wi-Fi system in Australia and will enable Canberrans to download 100 megabytes of data a day via 745 access points across the ACT.

The review, conducted by Brisbane-based consulting group Dynamic Wireless, recommended iiNet's proposal to the ACT government as a low-risk option but not without raising some objections and warnings.

The review noted that iiNet's proposal did not address how the company would protect Canberrans from viruses while using the free Wi-Fi network.

"They do not mention any hardware appliances or methods used to filter and protect users from viruses," the review said.

"As this is a mandatory requirement for the ACT government, this has been assigned an extreme-risk level."

But iiNet general manager for government relations David Parkes said email connections would be safe and secure despite declining to list further appliances or methods.

"The CBRfree network will be configured to only allow the sending of email from secure mail programs, including the likes of Gmail, Yahoo Mail and Microsoft Outlook," he said.

University of Canberra's Centre for Internet Security director Alastair MacGibbon has raised concerns the network would be exposed to the usual risks of public networks, although he said security would ultimately be determined by the vigilance of providers.

"The ACT government will have certain requirements as to how the free service is to be administered by iiNet, which should make the network no different to being on the net at home or anywhere else," he said.

The review warned it appeared iiNet was going to use its own performance metrics to assess performance and not take any ACT government input into account.

The consultants referenced iiNet's declared intention to "use its own internal customer experience measurement systems to determine the service levels for customers, including those that use the Wi-Fi networks".

"For this reason, a risk level of 5 (extreme) has been assigned, until such a time as this is clarified," the review said.

Mr Parkes said agreements on network performance would be audited independently once the network was constructed.

"The territory negotiated service level agreements during the consultation period for network uptime, network coverage and end-user access speeds," he said.

The review also found fault with the provisional plans for Wi-Fi coverage on ACTION buses – which will be a research trial – including the 10MB daily download limit and coverage issues.

"Considering that most passengers take return journeys on buses, 10MB will get used up very quickly on a smartphone or tablet," the review said.

"This equates to viewing about seven web pages for each one-way journey. Somewhere between 25-50MB would be more suitable."

Mr Parkes said the company would review the performance of the network and the download profiles of users during the introduction of the trial on buses.

"We are also actively investigating alternate technologies that leverage the Wi-Fi network to augment 4G coverage," he said.

The review acknowledged the company admitted it would be challenging to deliver iiNet's coverage and service expectations to buses.

"This is because mobile network coverage is not perfect, and a bus may have enough passengers on it to overload on mobile network connection," it said.

It said iiNet had decided not to integrate Wi-Fi coverage on buses with the broader network to avoid interference.