Omar Noun said trade has dropped off at his Aquarium Petroleum outlet since news broke on Monday that scores of northern suburbs residents had had their bank accounts skimmed.

He said many people had blamed the EFTPOS machine at his service station.

"We still don't know if it is or not," he said. "We haven't got anything back from the police.

"They couldn't find any proof of anything being done to it."

Mr Noun said the EFTPOS machine had been seized by police.

"It's affecting my business - I'm one of the victims of this, as well," he said.

"My business is very hard to run at the moment."

(It is not suggested that Mr Noun or Aquarium Petroleum is in any way involved in the fraud.)

Dozens of northern suburbs residents woke on Monday morning to find hundreds and even thousands of dollars had been illegally taken from their credit and debit cards since Sunday.

Some of the withdrawals had occurred in Canada and India while other were cash taken from Rockdale, Campsie and Kogarah.

Coledale's Sue Ganassin was among the victims.

"I found out on Sunday, I went to pay a bill and there was one dollar left in my account," she said.

"We lost $2420 out of our savings account, they had used both my card and my husband's card."

Ms Ganassin said she knew of quite a few other victims within her own circle of friends.

"I used to work for a bank and I had heard of it happening before," she said.

"My husband was really angry and I was sort of resigned to the fact. The bank will give it back, it will take some time and there's nothing much else I could do."

Ms Ganassin's bank called her on Monday when it was discovered fraudsters had attempted to use her card at Campsie Commonwealth Bank despite it being cancelled.