Federal government officials have defended the choice of a proposed trial site in Queensland to drug test welfare recipients, in the face of fierce criticism from the local council.
Logan was selected as a trial site partly because of sewage samples indicating high levels of drug use in the area.
However, it has since emerged the town's wastewater facility also treats parts of Brisbane, the Gold Coast and Scenic Rim.
Senior bureaucrats said the Queensland town was chosen for various reasons, including the fact Logan already had income management infrastructure in place.
"Ministers were provided with a number of factors and made decisions," Social Services secretary Kathryn Campbell told a Senate estimates hearing on Thursday.
Legislation underpinning the proposed drug testing trials is still before parliament.