The Australian Criminal Intelligence Commission has been testing sewage facilities for drugs, finding cocaine use is highest in Sydney.

Drug testing of 52 sewage plants across Australia has found cocaine consumption is higher in New South Wales than anywhere else, particularly in Sydney.

In its report on Monday, the Australian Criminal Intelligence Commission found Australia's cocaine use remained highest in NSW, with some parts of Queensland and Victoria also testing highly.

"Australians have an insatiable demand for all sorts of narcotics and synthetic drugs," the commission's chief executive Michael Phelan told reporters in Brisbane.

"That demand has not gotten any better."

Results from sewage testing carried out in February and April show a drop in fentanyl and oxycodone, but an increase in methamphetamine, cocaine, heroin and MDMA.

Levels of nicotine and alcohol have remained relatively steady.

Sewage analysis cannot differentiate between neighbourhoods or suburbs, and the waste being sampled is a mix of that flowing from prisons, hospitals, offices, homes, hotels and shopping centres.

It also cannot distinguish between prescribed or illicit opioids use, or whether nicotine intake is from tobacco, e-cigarettes, patches or gum.

"It's not a perfect science, but it's better than nothing," Mr Phelan added.

The commission aims to establish baseline data of substance use across Australia, claiming its data collection represents 55 per cent of Australia's population, or 12.9 million people.

Its results are used to inform government policy and decision making, as well as policing operations by providing the locations of tested sewage facilities, which are not publicly disclosed.

"There's been some areas in this country where particular catchment areas have shown high usage of a particular type of drug, in this case methamphetamine," Mr Phelan explained.

"After the result of the sustained policing operation of that area, we were able to show through the data that the usage went down."

The commission has received funding to continue its data collection for another four years.