Logan mayor Luke Smith has accused the Turnbull government of having an "atrocious" understanding of his city after it was named as the second site of the Commonwealth's drug-testing trial for welfare recipients.

Social Services Minister Christian Porter and Human Services Minister Alan Tudge will make the announcement in Beenleigh, south of Brisbane, on Wednesday.

Logan mayor Luke Smith said he had no idea about drug testing in Logan until a journalist told him. Credit:Robert Shakespeare

But Mr Smith said he had been given no information on the trial or why the city was chosen.

"We didn't even know this was happening in the city of Logan," Cr Smith told ABC radio.