Two members of the same family have died and another is seriously injured after a crash in Moreton Bay, north of Brisbane on Sunday. 

Police say a vehicle travelling west on the D'Aguilar Highway at Wamuran crossed onto the wrong side of the road, colliding with another vehicle at about 3pm AEST.

Two passengers in the eastbound car were killed and the female driver was seriously injured.

She has been taken to the Royal Brisbane and Women's Hospital.

Police say all three were related.

The male driver of the second vehicle has been arrested and taken to the Sunshine Coast University Hospital.

"The driver of the westbound vehicle has been arrested for dangerous driving," Inspector Craig White said. 

He said an off-duty paramedic had joined first responders to give aid. 

"Paramedics did an awesome job trying to save those people and I know that an off-duty paramedic also attended the scene at the time, also providing assistance," Inspector White said. 

He's appealing to anyone who saw the crash to contact police. 

"If there were any witnesses to the accident or anyone has dash cam footage, please contact Crimestoppers and advise us because their evidence may be crucial to this matter."