THE Australian Tax Office will not seek to expand its tax file number regime, despite the national auditor recommending the move to improve the agency`s electronic lodgement system.

The Australian National Audit Office (ANAO) recommended that the ATO approach the Treasurer to make legislative changes that would let government and private groups collect TFNs more frequently, in a report released last week.

However, a spokeswoman for the ATO said the agency was yet to identify a need for changes to the current scheme.

"At this stage we don`t have any intention to expand the TFN regime, but if we did come across a need to expand that, then we`d be discussing that with Treasury," the spokeswoman said.

Currently, the ATO matches data from across a wide variety of government and private agencies that process large numbers of financial transactions relevant to federal revenue collection.

They include Centrelink, the PAYG scheme, employers, Australian Transaction Reports and Analysis Centre, Veteran Affairs, child support agencies, and Medicare and private health insurers.

In its report last week, the ANAO argued that expanding the TFN regime would allow the ATO to make pre-filled electronic tax forms available to a larger number of tax payers.

The changes would go towards improving the ATO`s chances of reaching its goals under its Easier, Cheaper and more Personalised Change Program (ECMP).

The ECMP aims to take advantage of growing use of the internet across the population to reduce its processing costs.

The ANAO said expanding the TFN regime to a larger number of agencies more frequently would give the ATO`s data-matching practices the accuracy required to achieve its aims.

"Since the quotation of the TFN is not mandatory in Australia, there will always be transactions and records within data bases integral to tax administration that lacks this necessary numeric identifier," the ANAO wrote in its report.

"If the Tax Office`s identity matching engine fails to establish with a sufficient level of confidence the identity of the person belonging to the transaction or record, it may be necessary for Tax Office staff to investigate these transactions or records in order to link them reliably to a person and/or entity."

The ATO told the ANAO it agreed that it needed to accelerate its current pre-filling initiatives in written responses to the report.

But it said that any decision to expand the use of TFNs would need be balanced against the wider interests of the community.

"Where the inclusion of a tax file number on additional data sets is considered warranted to support the treatment of compliance risks, the matter will be discussed with Treasury," the ATO wrote in its formal response to the report.