Wollongong police have urged the public to pick up a phone instead of taking to a keyboard when reporting crime.
The advice came after the Mercury on Wednesday reported a Facebook group called "Move the junkies out of the Wollongong Mall & CBD", had been established in response to "drug-affected, undesirables who congregate and infect the local community".
Wollongong crime manager Detective Inspector Tim Beattie said while police found Facebook groups helpful at times when gathering information, officers needed the public to report crimes directly to police when they were happening.
He said people not reporting the crimes they witnessed was the "number one" issue frustrating police in their day-to-day duties.
"We need to deal with the incident at the time and not some time later," Insp Beattie said.
"We need to have the complaints made at the time so we can get down there to take ... action.
"We have a Facebook page at Wollongong police station as well, that's an appropriate place for people to ask questions ... but we want people to report crime at the time it happens."
He said police were "looking into" concerns raised in the "Move the junkies ..." Facebook page.
Many of the comments on the page were concerned with the number of clients from the Denison Street Methadone Clinic congregating in the mall.
However, Insp Beattie said people simply being in an area wasn't enough to warrant an arrest, regardless of the person's appearance.
"There are circumstances in which police can move people on ... if that person's behaviour meets a certain threshold," he said.
"But that's based on complaints, it's based on evidence and people informing police at the time."
On Wednesday, police were highly visible in the mall, tasked to "speak to shopkeepers and members of the public and seek any information" about any criminal activity in the area.
Insp Beattie said the police presence was part of ongoing operations in the mall and throughout Wollongong aimed at responding to public concern.
Insp Beattie also met Wollongong City Council representatives yesterday to discuss issues including law enforcement in the mall.