Police said the children, aged eight, seven, four and three, were taken by Joshua Carter, 28, from a property at The Leap, north of Mackay, in Central Queensland about 11.30am.
In an amber alert issued this evening, the Queensland Police Service said the children “may be at significant risk”.
“All of the children are described as being Caucasian in appearance with a slim build and brown hair,” police said in a statement.
Carter was said to have taken them from a Maraju Yakapari Road address in a white 2005 Nissan Patrol four-wheel drive.
The vehicle had Queensland number plates 063BC9.
The 4WD was last seen heading towards the Bruce Highway.
Carter is described as Caucasian in appearance with a solid build and 175 centimeters tall.
He has a shaved head, a full bushy beard, and multiple face and body tattoos including Joker-themed facial tattoos.
Anyone with information has been urged to contact police at the following numbers:
Call 131 564 to provide information about this abduction.
Call 000 for life-threatening information about this abduction.