A powerful cyclone has pummelled the north-east Australian coast, causing major damage, torrential rain and power cuts to tens of thousands of homes.
Cyclone Debbie made landfall between Bowen and Airlie Beach in Queensland as a category four storm, whipping gusts of up to 263km/h (163 mph).
It is moving inland as a category two but could cause damage for hours yet. One serious injury has been reported.
PM Malcolm Turnbull told parliament he had activated a disaster response plan.
"Conditions have deteriorated rapidly," he said. "Take care and stay safe. Be prepared to shelter in place until Wednesday."
He said defence force helicopters and naval vessels would be sent to Queensland with aid.
The extent of Cyclone Debbie's devastation, which has a 50km-diameter eye wall, may not be known for some time, authorities said.
Queensland Police Commissioner Ian Stewart said the storm's slow speed had created a "battering ram effect", adding: "We are going to get lots of reports of damage, and sadly I think we will also receive reports of injuries, if not death."
Queensland Premier Annastacia Palaszczuk said assessing damage was difficult because communities had been cut off from power and phone reception.
She said: "Everyone is going to be in shock tomorrow, just to see the full impact of this cyclone. I'm bracing myself for it."