Prague said Friday it was mulling a lawsuit against the National Geographic TV channel over a show depicting the Czech capital's historic centre as a hotbed of thieving cabbies, pickpockets, prostitutes and drug dealers.

Hosted by Irish presenter Conor Woodman under the tagline "I get scammed so you don't have to," the channel's Scam City show focused on 10 cities popular with tourists, including Prague.

In the Czech capital, Woodman is shown getting ripped off by a taxi driver, tricked by pimps and buying fake drugs on the street, but investigators believe some of the footage was staged.

"The police have concluded the report was shot using actors... which means it may have tarnished the reputation and good name of Prague," city councillor Lukas Manhart told AFP.

He added the city had asked to meet with National Geographic representatives, and an apology.

"If they decline to talk to us, we will consider legal steps," Manhart said.

But a local representative of the TV channel linked to the US-based National Geographic Society insisted there was nothing cooked-up about the show.

"We have enough shots to prove it's really authentic," Lada Dobrkovska told AFP.

Police spokeswoman Jana Rosslerova said detectives started a probe into the show as soon as it aired in November 2012.

"The police have dealt with all crimes featured in the show, but all evidence suggests the show was shot... by a crew of several members with... professional cameras the protagonists must have known about," she told AFP.

Rosslerova added the police have so far only talked to the actors who said they had been paid.

"Mr Woodman is not communicating with detectives for now, and detectives have said they may ask Interpol" to talk to him, she said.