One person is dead and others have needed rescuing from the roof of a car as a powerful offshore weather system batters Australia’s east coast.

The man’s body was found by police on Friday morning near Sandy Creek at Nanango, about two and a half hours north-west of Brisbane.

Elsewhere, the first day of the Splendour in the Grass festival near Bryon Bay was called off after 24 hours of chaos as thousands of fans faced hours-long queues and muddy campgrounds.

Festival organisers said they had cancelled performances on the event’s main stages for “today only”.

“A significant weather system is currently sitting off the east coast and may reach land later today, bringing more rainfall,” they wrote in a post on Facebook.

“In the interest of patron safety and in consultation with all relevant emergency services, we have decided to err on the side of caution and cancel performances on the main stages today only.”

They said they expected Saturday and Sunday programs to go ahead as planned.

Just hours earlier, they had closed the festival’s main campground at North Byron Parklands, while the NSW SES was called in to help manage the chaos.

Anyone still travelling to the festival was asked to head to Byron Events Farm at 35 Yarun Road, Tyagarah.

“We thank you for your patience here and big shout out to our staff who are working around Mother Nature to get you in here safely,” organisers wrote in a Facebook post.

“Please be kind and patient.”

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It followed a difficult day and night for many of the thousands planning to attend the event. Frustrated ticket holders took social media to air their grievances.

“Been in a car queue for 8.5 [hours], still potentially three hours from getting in the camp ground,” Harry Nicol posted to his Twitter after midnight.

Alex Gubbings told ABC News it took him about 12 hours to enter the Splendour grounds.

“I’d say we got in line around 4-4.30pm and we just got in at 4am,” he said.

Mr Gubbings said he was considering turning around at midnight and heading to a hotel.

“But my friends didn’t let me … we managed to just stick it out,” he said.

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Splendour co-founder Jessica Ducrou said organisers had planned for a wet event but faced “a new level of weather” on Thursday.

“Some things are just outside of our control and I think the actual volume of rain that we’ve had is way more than expected,” she told ABC radio.

Ms Ducrou blamed the wet weather and muddy conditions for causing the long queues. She warned that Friday would be “pretty challenging” for staff and patrons.

The 2022 Splendour in the Grass is the first in three years, after repeated cancellations during the pandemic.

In Queensland, police said the body recovered from floodwaters was believed to be that of a 47-year-old man. He is yet to be formally identified.

“We currently have officers from the dive squad who are en route to Nanango to assist with our inquiries,” Inspector Scott Stahlhut said.

The death followed the rescue of several people “in quite a dangerous situation” from the roof of a car at nearby Kingaroy, Inspector Stahlhut said.

An evacuation site has been set up at the local cultural centre and people have been moved from a low lying caravan park.

Flash flooding had hit the South Burnett region and drivers were urged to stay off roads.

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Rainfall totals of more than 100 millimetres were reported in the Sunshine Coast hinterland, with the town of Maleny among the hardest hit.

Forecasters also warned that damaging winds averaging about 50km/h were possible in exposed parts of the coast, while peak gusts might reach 110km/h on Fraser Island, also known as K’gari.

There was a minor flood warning for the Stanley River at Woodford, about an hour north of Brisbane.

The low-pressure system is expected to move south on Friday and Saturday, and beaches have been closed on the Gold Coast due to the dangerous conditions.

Across the border, wild weather has hit the NSW Northern Rivers district, with the Bureau of Meteorology issuing a severe warning for damaging surf north of Yamba on Friday night.

Waves of more than five metres are possible before conditions begin easing on Saturday afternoon.

“Beach conditions in these areas could be dangerous and people should stay well away from the surf and surf exposed areas,” the bureau said.

-with AAP