Thousands of Queenslanders face another major flood emergency, with heavy rain battering the state’s south-east expected to last well into Saturday.

Up to 160 millimetres of rain was forecast to fall the region on Firday, with half a dozen emergency flooding alerts issued by lunchtime.

Hundreds of homes are under threat and dozens of roads and schools have been closed as the floodwaters rise.

By early Friday afternoon, alerts were in effect across Gympie, Lockyer Valley, Warwick, Millmerran, Mount Tarampa, Minden, Patrick Estate, Stanthorpe, and the Scenic Rim.

There are also minor flood warnings for a host of rivers in northern NSW, as the dangerous front tracks south.

Friday was originally expected to be the peak of the weather that has wreaked havoc across much of Queensland this week. But the weather bureau altered its forecast early in the day, predicting another day of heavy rain to follow.

“This is an evolving situation,” Bureau of Meteorology senior forecaster Laura Boekel said.

“That weather is likely to stay around today, and into tomorrow, tomorrow is now and we will start to see the clearing trend.”

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Premier Annastacia Palaszczuk said the rain was not as constant and intense as downpours that caused major floods in February, but would linger longer than first forecast.

She said the main concern was for communities along the flooding Condamine, Logan, and Bremmer rivers, as well as Warril, Laidley and Lockyer creeks.

“If you don’t need to be out and about on the roads in the south-east, please don’t travel unless you absolutely must,” Ms Palaszczuk said on Friday.

“Please remember: if it’s flooded, forget it.

“Please don’t be anxious. The key thing is to be listening to the alerts and we’ll be keeping everybody updated as much as possible.”

Laidley residents were being evacuated on Friday. Floodwaters had affected 300 homes in the town, west of Brisbane, while a brown torrent was gushing down the main street after Lockyer Creek rose to a major flood level.

People in other low-lying parts in nearby Grantham, Gatton, Mount Tarampa, Minden, Patrick Estate and Prenzlau had also fled or were preparing to do so.

South of Toowoomba, a major flood was underway on the Condamine River, with homes at risk at Warwick, Millmerran, Cecil Plains and Cooby Creek, while flash-flooding was occurring near Killarney and Stanthorpe.

The Logan River broke its banks at Beaudesert, south of Brisbane, and reached a major flood level, while the Mary River was flooding at Gympie.

The Brisbane River was not expected to rise above a minor flood level.

But Ms Boekel warned that flash flooding remained a risk in saturated creeks and streams across the city.

“Areas within that severe weather warning area are at risk of seeing more intense rainfall within the widespread band, and that’s where we can start to see flash flooding, and that’s when the situation can become potentially life threatening,” she said.

Almost 740 roads are closed or impacted by floodwaters and authorities have closed more than 70 schools due to the weather.

South of the border, the BOM has also warned of likely flooding in the northern rivers region in the next 24 hours. Affected rivers include the Lower Macquarie, Clarence, Macintyre, Severn, Bogan, Castlereagh, Culgoa and Paroo.

“There has been heavy rainfall across parts of the border rivers, especially around Stanthorpe, which has experienced rapid river level rises overnight Thursday into Friday morning,” the bureau said.

“This flood water and additional inflows along the Severn River will combine with inflows from the Macintyre River in NSW, which is expected to result in minor flooding at Goondiwindi and Boggabilla during Saturday. Major flooding is possible at Goondiwindi late Sunday into Monday.”

Queensland Deputy Police Commissioner Steve Gollschewski said people in flood zones should stay connected, listen to warnings and take action at the right time.

Meanwhile, a powerful easterly swell and strong onshore winds have whipped up four-metre waves with the BOM warning of dangerous surf conditions and possible coastal erosion between Fraser Island and the NSW border.

The unseasonal deluge is Queensland’s sixth deadly flood since December, which scientists have put down to a second La Nina weather pattern in two years.

-with AAP