An American who claims to have been on a mission to hunt down Osama bin Laden has been arrested in northern Pakistan armed with a pistol, dagger and a sword, police said.

The 50-year-old man from California was detained in the mountains of Chitral district near the border with Afghanistan's Nuristan province, a known stronghold of the Taliban, police officer Mumtaz Ahmad Khan said.

Police identified the suspect as Gary Brooks Faulkner.

Police said he arrived as a tourist, checked into a local hotel and was given the customary security escort for his own safety before he disappeared on Sunday night.

"Our security guard noticed that Gary had disappeared. A search operation was launched and we found him 14 kilometres short of the Pakistan-Afghan border. He was trying to enter Nuristan," said Mr Khan.

"He said 9/11 caused colossal losses to the US, therefore he wanted to locate Osama bin Laden and his friends. We presume he came here with an intention to kill them."

The daily Dawn newspaper said Faulkner acknowledged to police that he wanted to "decapitate Osama bin Laden".

Mr Khan described the suspect as suffering kidney problems and high blood pressure but of sound mind.

The US consulate in Peshawar was notified on Tuesday that an American citizen had been arrested.

"We are now working on getting consular access and meeting with the American citizen," a spokesman for the US embassy in Islamabad said.

Saudi-born terrorism mastermind bin Laden, now in his 50s and rumoured to be in poor health, is the world's most-wanted man with a multi-million dollar bounty on his head.

- AFP