PARIS (Reuters) - Thermal cameras will be used at the Tour de France to detect motors in bikes, the French Sports Secretary of State said on Monday.

In a joint news conference with Tour de France director Christian Prudhomme, French cycling federation president David Lappartient and International Cycling Union (UCI) head Brian Cookson, Thierry Braillard explained that there would be random checks on the July 1-24 Tour.

"With this technology which has been approved by the UCI and by the Tour de France (organizers), those who will want to cheat will be taking very very big risks," Braillard said.

"It's a complement to what the UCI has been doing."

"Those who want to cheat can be worried," said Prudhomme.

The thermal cameras have been set up by the French Alternative Energies and Atomic Energy Commission at the request of the government.

The UCI has been using magnetic resonance testing to detect motors. Both methods should be used on the Tour.

The magnetic resonance testing helped the UCI find one motor earlier this year in the bike of Belgian Femke Van den Driessche at the Under-23 cyclocross world championships.

Two months ago television station France 2, in collaboration with Italian newspaper Corriere della Sera, reported that hidden motors were used in the Strade Bianche one-day race and the Coppi e Bartali race in Italy this season.

The report used thermal imaging to show that five motors were hidden in the seat tube and two in the rear hub, but added they could not prove it beyond all reasonable doubt.

(Reporting by Julien Pretot; Editing by Ed Osmond)