5-year-old girl, Queensland couple found dead

5-year-old Kayla Rogers. Photo / Supplied

A five-year-old girl, abducted from a Gold Coast unit that's the scene of a likely double murder, has been found dead.

"With great sadness we advise that the New South Wales Police Force have located a vehicle with the deceased bodies of a five-year-old girl and a man in a car just outside of Casino," Queensland Police said in a statement on Monday night.

Police found a 2006 model silver-coloured Holden Viva with the two bodies under the Piora Bridge, near Casino, in northern NSW, shortly after 9.30pm (AEST) on Monday.

The young girl was believed to have been taken from the unit on Arbour Avenue, at Robina, by a man overnight.

Police had information that the man fled across the border into northern NSW near Casino or Kyogle with the girl and that her disappearance was linked to what is believed to be a double murder.

A relative of the victims found the body of a man in the Gold Coast unit about 8am on Monday.

The woman's body was found later, after police were called to the property.

Detective Inspector Brian Swan earlier said there were signs of a struggle and both bodies had suffered some sort of trauma.

Forensic officers combed the unit to try to piece together what had happened and police door-knocked neighbours throughout Monday.

They initially believed two children were missing, but a baby boy was later found safe and well.

A full investigation is underway involving specialist police from NSW and Queensland.

_AAP