An Emirati arrested in Tripoli on suspicion of spying on Libyan authorities in charge of the capital was an ex-sergeant dismissed by Dubai police five years ago, the force said on Twitter.

The unnamed suspect was arrested on November 5 and is being questioned, Siddick al-Sour, the head of the prosecutor general's office in Tripoli told AFP.

He said the United Arab Emirates national is connected to the police in Dubai and was on his third visit to Libya since 2012.

"He claims to be a businessman and to have no ties to the Dubai police but intelligence agents found pictures on his phone of sensitive locations in Tripoli, including a video of the Turkish embassy," said Sour.

Dubai police chief Khamis al-Muzainah said in a late Wednesday statement on his force's official Twitter account that the charges against the man were "false and far away from truth."

"The arrested suspect's relation with the police had ended five years ago (in 2010) when he was dismissed from military service for his involvement in a moral case," said Muzainah.

Libya has had two administrations since August 2014, when an Islamist-backed militia alliance overran Tripoli, forcing the internationally recognised government to take refuge in Tobruk, in the far east of the country.

The oil-rich north African country descended into chaos after the fall of Moamer Kadhafi in its 2011 revolution.

Authorities in Tripoli accuse the UAE of supporting the internationally recognised government and has accused the UN's outgoing Libya envoy of a conflict of interest for accepting a high-paid job in Abu Dhabi while mediating peace talks.

*This story was edited by Ahram Online.