The live broadcast of the finale of Germany's Next Top Model was unexpectedly cancelled and the set evacuated after an apparent bomb threat.

Nearly 10,000 spectators were ordered to evacuate the SAP Arena in Mannheim, Germany, about 9pm local time (5am AEST), according to reports.

Bild.de reporter Daniel Cremer tweeted that Heidi Klum and other judges on the show were the first to leave the area, before the audience was escorted to the car park.

A spokesman for Mannheim police told local reporters the organisers had decided to clear the venue and end the show after an unidentified female person called in a bomb threat.

He said police are now investigating the alleged threat.

SWR News tweeted that police were not initially aware of the bomb threat and it was the event organisers who ordered the evacuation.

Audience members were told to go home after a short time waiting around in the car park.

The audience was evacuated from the SAP Arena. (Twitter)

Television station ProSieben, which was due to broadcast the finale, aired a feature film instead, after initially blaming the swap for a technical issue.

Heidi Klum's father and manager Guenther Klum was approached by Spiegel Online but he has declined to comment at this stage.

Four young women were competing in the finale of the 10th series of the show, which is one of Germany's most popular television programs.

This is a breaking news article. More information will be added as it comes to hand.