Auditor-General Dr Maxine Cooper has been investigating several rural land buy-ups by the former LDA since May last year, in an audit expected to be released in March.

The audit targeted all rural land purchases since 2012, including the more than $20 million the LDA spent buying rural properties in 2015-16.

But that probe has since widened to include the government's purchase of the $7.5 million Winslade property, in a deal completed on the former LDA's final day of operations before its abolition on July 1 last year.

Answers to a series of questions on notice posed by the Opposition during annual committee hearings in the Legislative Assembly late last year have also shed more light on the nature of some of the LDA's rural land deals.

Asked by Opposition leader Alistair Coe how many "peppercorn leases" the LDA had issued, the government said there were four, each "with terms being a period of 10 years at a nominal rental rate with all ongoing costs of maintenance, rates and charges met by the sub-lessee".

But those purchases were completed despite the former LDA having "no policy on the issue of sub-leases".

Such arrangements, the answers read, were "considered on a case by case basis dependent on land management requirements, the size and nature of the property, the future purpose and timing of development".

The government has also confirmed the four deals were: the Winslade land at Mt Stromlo and the $4.6 million purchase of Pine Ridge in Belconnen last year, Wintergarden at Belconnen in 2016 and Horsepark in 2011, each sub-leased back at a rate of $1 a year.

A government spokeswoman said that in all four purchases, a sub-lease was used because "the land will not be required for urban use for some years, and [each] seller expressed interest in continuing to manage the property".

It remains unclear if the audit investigation will also extend to the Pine Ridge purchase, which was organised by the LDA, but settled by the new Suburban Land Agency under the LDA's old acquisition policy in July last year.

The Auditor-General has confirmed, in an answer to another question on notice, that the audit's scope includes Winslade, but Dr Cooper would not comment further when The Canberra Times sought more details.

Asked why the Winslade and Pine Ridge purchases were made in the LDA's final months of operation, given Chief Minister Andrew Barr pledged to abolish the agency in 2016, the government spokeswoman said the acquisitions started in 2016.

She said work on both purchases began "well before there was a government decision on changes to the LDA".

"The LDA continued to operate in a business as usual manner right through to the transition to the SLA," she said.

"Many transactions were carried over between the two organisations."