One retailer on Railway Parade said they were spat on, another had furniture smashed and others have experienced theft and fraud from drug-addicted patients.

Several shop owners said they had called police to complain about people loitering on Railway Parade. "They scare away my customers and so many customers complain about it," one said.

"It's a big problem. Sometimes they break tables and chairs.

"I told them they're not welcome but they still come. What can you do?"

St George police crime manager Detective-Inspector Gary Ballard said police regularly patrolled past the clinic and recently arrested a clinic patient for dealing in prescription drugs. But Mr Ballard said people did not always report illegal activity, press charges or help police prosecutions.

"We do rely on the community," he said. "We definitely urge anyone who has problems down there to contact us."

A spokeswoman for the South Eastern Sydney Local Health District said the clinic held a quarterly forum for the public to discuss a range of matters and was aware of their concerns. She said the clinic performed a vital service and patients should not be banned from the Railway Parade shopping strip.

"It's unfeasible to try to ban clients from the Kogarah area given most clients live in the Kogarah area and use local shopping and other facilities," she said.

"Such geographic bans can only be enforced as part of a legal order in response to a criminal offence and we're not aware of any such orders with our client population."

The Kogarah clinic had shifted its focus to "more complex treatment needs" to reduce its client base.

"Many patients with less complex needs transfer their opioid treatment to general practitioners and pharmacies in the community and no longer attend the clinic," she said. "This has led to far fewer methadone and buprenorphine patients at the clinic."

Should the methadone clinic in Kogarah stay open?What do you think is the best way to solve the problem?