Demolition firm Irwin and Hartshorn have been awarded a $427,000 contract to raze four vacant buildings at Dickson's Block 6, including the union's old offices.

Work is scheduled to start later this month and be completed in April.

Prior to demolition, the contractor will be required to remove non-friable and friable asbestos which has been found at the site. In an email this week, the goverment's 'Section72 team' stressed the material was not the "loose fill Mr Fluffy asbestos".

The Rosevear Place block was at the centre of a controversial 2014 land deal between the ACT government and the union-linked Tradies club, which is now the subject of an ACT Assembly inquiry.

As part of the deal, the government bought two blocks of land at Section 72, in return for selling a carpark outside the club. The audit office found the deal gave the club concessions worth up to $2.65 million.

The union last year moved to new headquarters on Cape Street, Dickson.

Securing the 5233 square metre site was crucial to the government's long-term plan of rejuvenating Section 72 with housing, open spaces and upgraded cycleways and footpaths.

The government has earmarked Block 25 as the site of its second Common Ground project, which will co-locate low-cost housing with support services.

The wider plan for the precinct has yet to be unveiled, but preliminary concept designs showing buildings of up to four storeys across the precinct sparked alarm among local residents.

The North Canberra Community Council last year wrote to the government calling for the site to retained for community and cultural purposes amid concern "bulky apartments" could dominate the redeveloped site.

In her response, Urban Renewal Minister Rachel Stephen-Smith said the inclusion of new housing at Section 72 would "not necessarily reduce the site's overall capacity for community uses".

This week, Dickson Residents' Group convenor Jane Goffman accused the government of a lack of transparency surrounding the future of Block 6, claiming information about the demolition had not been disclosed when the project was announced in January last year.

Ms Goffman said the community first learned plans to demolish the site when a development application was released for public consultation in late July.

But Geoffrey Rutledge, a deputy-director general at the government's environment, planning and sustainable development directorate, said it had presented information showing Block 6 as a "future opportunity site" during community workshops on Section 72 between January and June last year.

Mr Rutledge said funding for demolition work was included in the ACT budget last June, before the formal development application was lodged.

He said the site's four buildings had no heritage value, and their age, design and condition meant the potential for refurbishment and reuse was "extremely restricted".

The demolition would ward off vandalism, and marked an "essential early step" in the wider redevelopment of Section 72, he said.