A drug and alcohol treatment centre on the front line of the federal government's cashless welfare card trial says the program is not reducing substance abuse.

South Australian Aboriginal Drug and Alcohol Council chief executive Scott Wilson, who oversees the largest drug and alcohol centre in Ceduna, South Australia, said those in the program still found a way to feed their drug and alcohol addictions.

The South Australian town of Ceduna has been trialling the cashless welfare card since 2016. Credit:Alex Ellinghausen

Ceduna, on the shores of Murat Bay about 786 kilometres north-west of Adelaide, has been trialling the cashless welfare card since March 2016.

"We haven't seen a decrease whatsoever in people coming," Mr Wilson said of the Stepping Stones Drug and Alcohol Day Centre, which has nearly 20,000 client contacts a year. "I keep hearing the rhetoric from the government about how successful these trials are. We've sort of said from our point of view people obviously still have access to alcohol."