Two of the motorcyclists died at the scene while the five casualties were taken to hospital by ambulance and air ambulance.
Inspector Gareth Jones, of North Wales Police, said: "The incident involved a car and six motorcycles - two riders of which sadly passed away at the scene.
"Five further casualties were conveyed to hospital by the Helimed and ambulance. An update is awaited on their condition. Officers remain on scene continuing with their investigations."
The identities of those involved in the crash have not yet been disclosed.
Diversions have put in place while investigators examine the scene