Cody Wilson, the US man who gained an international profile due to his legal fight over 3D-printed guns, is wanted on an arrest warrant over an allegation he had sex with an underage girl he met on a "sugar daddy" dating website.

Key points: Authorities are trying to locate Cody Wilson who was scheduled to return from Taiwan to the US

Authorities are trying to locate Cody Wilson who was scheduled to return from Taiwan to the US It is alleged Mr Wilson had sex with a 16-year-old girl at an Austin Hotel

It is alleged Mr Wilson had sex with a 16-year-old girl at an Austin Hotel The girl says he paid her $US500 afterwards and dropped her off at a fast-food restaurant

Austin Texas Police Commander Troy Officer said at a news conference on Wednesday Mr Wilson was scheduled to fly back to the US from Taipei, Taiwan, but he did not board the plane.

He said his department was working with national and international law enforcement to locate Mr Wilson, who did not reply to a phone message from The Associated Press seeking comment.

Commander Officer said it was unclear why Mr Wilson went to Taiwan, but he is known to travel extensively.

He said before Mr Wilson flew there, a friend of the girl told Mr Wilson that police were investigating her claim he had sex with her.

In a court filing, Detective Shaun Donovan said Mr Wilson had sex with the 16-year-old girl at an Austin hotel on August 15.

He said Mr Wilson met the girl through a "sugar daddy" dating website, and they met in the parking lot of an Austin coffee shop before they drove to the hotel.

The girl told investigators Mr Wilson paid her $US500 ($688) after they had sex and then dropped her off at a fast-food restaurant.

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Video surveillance shows Mr Wilson and the girl getting out of a vehicle at the hotel and then exiting an elevator together on the seventh floor, Detective Donovan wrote. The footage shows them returning to the elevator later that night.

Hotel records revealed Mr Wilson was registered in the same room that the girl reported he had sex with her in, the detective wrote.

Mr Wilson is identified in the affidavit as the owner of Austin-based Defence Distributed.

After a federal court barred Mr Wilson from posting the printable gun blueprints online for free last month, he announced he had begun selling them for any amount of money to US customers through his website.

The states sued to stop an agreement that the Government reached with Defence Distributed, arguing that the blueprints for how to print plastic guns could be obtained by felons or terrorists.

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AP