The Bureau of Meteorology said there was major flooding in the Wide Bay and Burnett regions, north of Brisbane, causing highways to close and cutting off some towns.
Marodian near Gympie received more than 670mm in the 24 hours to 9am with many other areas receiving at least 300mm
The Bruce Highway reopened late Saturday morning after the downpour forced it to close earlier.
There were warnings for more heavy rain on Saturday and authorities issued an emergency alert for Maryborough, urging people to reconsider travel.
Queensland Police confirmed one person had drowned after his vehicle became submerged in flood waters at Kanigan, Wide
Police and emergency services responded to reports of a ute being swept off the road on Cherry Tree Road near the Bruce Highway about 7.30pm.
The driver, a 22-year-old Sunshine Coast man, was found inside the vehicle on Saturday morning. No one else was in the car at the time.
Police had been called to rescue 23 people in 11 vehicles. Eight of those were now safe, but the remaining 15 people were unaccounted for with rescue crews unable to access many areas.