Thieves were targeting drunk partygoers at parties, Mr Holdsworth said.
"And watch what you're drinking, it may be that not everyone is in a party mood and some people may be laying in wait, ready to take not only advantage of you and your credit card as well.
"Then while no-one is watching or able to pay attention, a victim's credit card is stolen."
Recently, a victim had gone to sleep on the couch in an apartment and left her door open.
"When she awoke she found an opportunist burglar had darted in, stolen her card and already made a number of purchases," Mr Holdsworth said.
In another example, a card was stolen in the middle of the day and used in four service stations to make purchases over a 25 minute period.
A total of $113.79 was spent at two service stations where the third and fourth attempt was declined.
The most common items purchased with the stolen cards were cigarettes and tobacco, alcohol, snacks and fuel, he said.
Police advised the public to immediately notify their bank and police if heir card was stolen, so it can be cancelled.