Rising flood waters will likely isolate some Gold Coast residents and evacuations have been ordered in northern NSW as heavy rain continues across the region, bringing major flooding.
An emergency alert has been issued for the Tallebudgera Valley, which is expected to be cut off as roads are inundated.
"You should prepare for short term isolation," the Gold Coast council warned in a statement on Thursday.
At nearby Springbrook, in the Gold Coast hinterland, a massive 380mm had fallen in the 12 hours up to midday, with as much as 500mm predicted.
Meanwhile, the extreme weather has forced authorities to suspend a search for a bushwalker missing in a national park on the Queensland-NSW border.
A landslide on the Lamington National Park's access road is stopping authorities heading in to look for the man, aged in his 60s.
He went hiking on Wednesday but failed to meet up with friends at 2pm, as agreed, and last made contact with authorities later that day.
Over the border in far northern NSW, residents have been ordered to evacuate ahead of major flooding.
The NSW SES has advised residents within the South Murwillumbah, Condong and Tumbulgum areas to leave immediately.
Major flooding is forecast along the Tweed River with The Bureau of Meteorology predicting levels to be similar to the 2001 and 2008 floods.
During the past day up to 398 millimetres of rain has been recorded in the Tweed Valley.
Major flooding is also forecast to the north of the Gold Coast on the Logan and Albert rivers, along with damaging winds gusting up to 90km/h.
"Bureau of Meteorology predictions indicate water levels in the rivers could reach peak levels similar to the 2013 flood event," a Logan City Council spokesman said.
"We are urging people living within the vicinity of flood-prone areas to monitor the rising water levels and prepare to take action for their own safety and their families."
Flash flooding has caused more than 105 roads to be closed in the area and about 1200 homes are without power.
Five sandbag collection points have been set up and the council is warning people to expect delays around depots.
