Recent instances of counterfeit tickets at Green Bay Packers home games has prompted local officials to caution fans to check the authenticity of tickets for upcoming NFL playoff games.

Police seized about 25 fake tickets at Lambeau Field during the December 25 game against the Chicago Bears, costing buyers thousands of dollars, according to the Green Bay Press-Gazette. Counterfeit tickets also were reportedly discovered at the Packers' December 11 home game against the Oakland Raiders.

Most of the tickets were bought outside of Lambeau, police told the Press-Gazette, though some were purchased on Craigslist.com.

The defending Super Bowl-champion Packers host the New York Giants on January 15 in a Divisional-round playoff game. A Packers victory this weekend also would make Lambeau the site of the NFC Championship Game on January 22 against either the New Orleans Saints or San Francisco 49ers.

To head off additional counterfeit problems, the team posted a warning on its Web site reminding fans to be wary when purchasing tickets from "secondary or unofficial sources." Licensed Green Bay-area ticket brokers echoed the team's advice: Know who you're buying from.

"We know what to look for," broker Jim Bryce Jr., a partner at Ticket King in Green Bay, told TicketNews. "It'd be hard to get [counterfeits] past us."

Green Bay police Lt. Kevin Warych told the Press-Gazette that counterfeit tickets were also a problem in the 2008-2009 season and that fakes usually become more prevalent for high-demand games.

On the Packers Web site, Warych added, "The best advice we can give is to do your research and know your source."

The Packers site, meanwhile, urged fans to use team partners Ticketmaster and Packer Fan Tours. There is also a designated area outside Lambeau for licensed resellers, who must display a permit.

"I've never come across fake tickets here," said Mike Holzberger, owner of Connections Ticket Service in Milwaukee, to TicketNews. "I don't think anybody would try to sell them to me, because they'd be sure that I would spot them. A fan buying them on the street, or buying them in bars, might not know the difference."