Local merchants are being warned to be on the lookout for counterfeit cash after five bogus $100 bills surfaced at several locations around Whitehorse.

"The way I'd describe the metallic strip (on the counterfeit $100 bills), if you look at it under the light, it will reflect a '10'," RCMP Sgt. Mark Groves told the Star early this afternoon.

"It looks like whoever did this removed (the strip) from a $10 bill and applied it to the (fake) $100 ... it's a giveaway."

Police were first alerted to the funny money last Tuesday after a Porter Creek Super A customer used one to pay for gasoline.

"One of our gas bar attendants took it and when our office manager did the deposit the next day, she noticed it," said Super A store manager Mike Sheppard.

"(And) another one went through one of our tellers at the front end of the store the next day."

In all, five bogus bills have been passed in what Sgt. Groves described as an opportunistic crime likely perpetrated by a small-time operator.

"(Counterfeit cases) seem to surface at busier times of the year, when the teller is preoccupied or someone taking advantage of Christmas rush when clerk is inundated with shopping traffic," said Groves.

The quality of the fake $100s and the limited incidents have all but ruled out a large-scale counterfeit operation.

"I would say it's more localized... a lot of our frauds, our e-mail frauds, phone frauds are generally a national or international issue," he said. "This is more a localized issue; there's not an overwhelming amount except for those who are stuck with it and hopefully that number stays low."

And Super A's manager agreed.

"This has happened a few times to us (in the last several years) but it's not very common," said Sheppard.

The counterfeit bills all share the same serial number - BKC6212387 - and the images on the bill, which features former prime minister Robert Borden, lack sharpness when viewed closely, according to police.

Police are advising the public to be vigilant when receiving bank notes of all denominations and to examine security features carefully.

These features can be felt through genuine bills' embossing (raised dimples for the visually impaired) and can be viewed by tilting the bill to examine the holographic strip.

If you have received any bills that you suspect may be counterfeit, please contact your local RCMP detachment.