The Land Development Agency is billing the sale of the 12ha off the Monaro Highway as ''Canberra's largest industrial subdivision opportunity''.

The artefacts understood to be flints and tools have been removed from the site, according to the Government.

The englobo land parcel, just north of the ACT Resource Recovery Centre, goes to public auction on August 8. The Government would not speculate on any likely return for the land but expected ''market demand for the site to be strong''.

Commercial real estate agent Jones Lang LaSalle is selling the land on behalf of the Land Development Agency.

The marketing has emphasised the site's proximity to established industry in Hume, its high visibility from the Monaro Highway and its potential for a large-scale industrial development of at least 12 blocks.

The parcel up for sale is part of the site which was ActewAGL's second-preferred option for the power station and data centre.

The Land Development Agency had referred ActewAGL to the site, after another block in Hume ActewAGL's first preference was sidelined for sale for industrial use.

In July last year, the Land Development Agency identified concerns by Heritage ACT that the second Hume site was rich in indigenous cultural artefacts and a heritage study would need to be done.

ActewAGL was initially prepared to contribute $100,000 towards the heritage study.

It eventually decided against proceeding on the second Hume site due to the time and costs involved with the heritage study. It ultimately chose to site the power station and data centre at Macarthur instead, prompting outrage from residents who said the proposed development was too close to homes.

A government delegation to The Canberra Times last month provided a document which said of the second Hume site, ''ActewAGL decided that this [heritage study] introduced an unacceptable degree of uncertainty into the development process given the time pressures and the possibility that the site may not be usable after the recovery process of artefacts and so decided to pursue an alternative site.''

But, while the Aboriginal artefacts prevented ActewAGL from proceeding with the power station on the Hume site, they appear to no longer be stopping other potential projects.

A spokeswoman for Chief Minister Jon Stanhope said yesterday, ''The concerns of ACT Heritage have been resolved through appropriate recovery of the artefacts by the [Land Development Authority]. All recovery action has now been completed and the land is approved and cleared for development.''

Chief Minister's Department deputy chief executive David Dawes said last night all the Aboriginal artefacts had been removed from the site before the land was advertised for sale and were in safe storage. An archaeological dig by consultants had been under way for some months.

Opposition MLA Brendan Smyth asked Mr Stanhope in the Assembly earlier this month a question without notice about an investigation into the indigenous artefacts on the site.

Mr Smyth said he assumed the investigation must have been completed because the site had already been advertised for sale in The Canberra Times.

''Have there been any discussions as to whether the proposed power station and data complex could now be developed on this block?,'' Mr Smyth asked.

Mr Stanhope said in reply that the investigation into the indigenous artefacts was due to be completed on July 9, pending weather conditions.

He also agreed the Hume land had been advertised for sale on June 28 in The Canberra Times.

''No, there have not been discussions as to whether the power station and data complex could now be developed on this block,'' Mr Stanhope said.

''ActewAGL has selected its preferred site at Block 1671 Tuggeranong and is proceeding with a development application.''

Opposition Leader Zed Seselja asked yesterday why the land had been marketed before the indigenous artefact investigation had been finished.

''Why on June 28 when it was advertised, was it deemed suitable for industrial use but that was prior to the completion of a study on whether or not indigenous artefacts would prevent development, presumably?''

Mr Dawes said a written report about the investigation was due on July 9 but the Government ''already knew what the outcome was'' so started marketing the land.

''The investigation had been finished by the time they started advertising and we were just waiting for the documentation to arrive,'' he said.

Mr Seselja said the Hume site in an industrial area was ''more suitable'' for the power station and data centre than the Macarthur site.

''It's further away from homes and I think it has more natural barriers between it and residents,'' he said.

However, Canberrans for Power Station Relocation spokesman Rodahn Gibbon said the Hume site would not have been acceptable for the project either, because it was still too close to homes in Tuggeranong.

''We are sceptical about the whole site selection process,'' he said. Mr Gibbon said a site for the power station should have been chosen through the guidance of a full environmental impact statement, something residents still wanted.