Burglars took valuable equipment from a site in Belfast Terrace during the first incident.
The second burglary took place at Hanley Downs, where Queenstown's largest housing development is being built.
The Hanleys Farmsubdivision is projected to have 1750 sections.
Tools and a trailer carrying a small digger were stolen in the second burglary.
The value of items taken from the Hanley Downs site was unknown.
Both incidents were reported on Monday. Police could not confirm the time either burglary took place.
Senior sergeant Paula Enoka, of Queenstown, said officers would now be doing theft prevention work with construction sites.
''We have a lot development at the moment.
''Make sure your property is well marked and well secured and if possible, removed from the site.''
The incidents followed two burglaries at the Queenstown Country Club development site last month, which took place over the same weekend.
Several tools and items of building equipment were taken from the site.
