An official involved in the investigation said that the crime did not appear to be political.
The official, who was speaking anonymously, said: "Our first impression is that it's not politically motivated."
The Lebanese official said her body was found "on the side of the Emile Lahoud road", just north of Beirut.
He confirmed the victim's name was Rebecca Dykes but could not elaborate on the exact circumstances of her death.
The official said investigators are looking into reports that Dykes had been sexually assaulted.
British Ambassador to Lebanon, Hugo Shorter, said: "The whole embassy is deeply shocked and saddened by this news.
"Our thoughts are with Becky's family, friends and colleagues for their tragic loss.
'We are providing consular support to Becky's family and working very closely with the Lebanese local authorities who are conducting the police investigation."
She joined the Department for International Development and had been working as a programme and policy manager based in Lebanon since January.
Before she moved to Beirut she worked for the Foreign and Commonwealth Office on the Libya team as a policy manager. She had previously worked as an Iraq Research Analyst with the FCO.
The University of Manchester graduate also had a masters in International Security and Global Governance from Birkbeck, University of London.
A family spokesman said: "We are devastated by the loss of our beloved Rebecca. We are doing all we can to understand what happened.
"We request that the media respect our privacy as we come together as a family at this very difficult time.'
A spokesman for the Department for International Development where she worked said: "Our thoughts are with Becky's family and friends at this very upsetting time.
"There is now a police investigation and the FCO [Foreign Office] is providing consular support to Becky's family and working with the local authorities."
A Foreign Office spokesman added: "Following the death of a British woman in Beirut, we are providing support to the family.
"We remain in close contact with local authorities. Our thoughts are with the family at this difficult time."