A huge swathe of Australia’s east coast is bracing for days of wild weather and cyclone-like conditions, with torrential downpours, towering swells and abnormally high tides.

Coastal towns were swamped in Queensland and NSW at the weekend as extreme conditions coincided with king tides to produce some of the highest tides of the year.

Byron Bay’s famous Main Beach had barely a grain of sand visible late Sunday as massive swells pummelled the coast and sparked warnings of severe erosion.

In southeast Queensland, conditions have been likened to a category 1 cyclone as thundering waves – which averaged 5 metres but were as high as 10 metres – slammed shorelines from the Sunshine Coast to the Gold Coast and look set to continue.

A daredevil surfer makes the most of huge swell at Snapper Rocks on the Gold Coast on Sunday. Picture: AAP

The Bureau of Meteorology said heavy rain, cyclonic winds, flooding and dangerous surf were forecast across the two states for several days.

The weather bureau has issued flood warnings for a vast area stretching from Bundaberg in Queensland to northern NSW as the powerful weather event dumped up to 500mm in parts, with some rainfall records broken.

The BOM on Sunday warned that wild weather affecting northern NSW was building up as heavy rainfall over the weekend caused river rises.

Byron Mayor Simon Richardson told the ABC he was nervous about the combination of factors creating the perfect storm.

“Everyone is nervous who has an understanding of the implications,” he said.

“We’ve obviously had a lot of storms over the years but we also know there are some erosion issues there that are – I mean, I don’t want to over use the word unprecedented, but it’s certainly a real confluence of different conditions.”

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Minor flooding was expected at Lismore on Sunday night, with further rises to the moderate flood level possible late on Monday and into Tuesday.

Heavy rainfall was expected to become severe again over parts of the Mid North Coast and Northern Rivers from Sunday night into Monday morning.

Flooding in Brunswick Valley, Northern NSW. Photo: ABC

“Rainfall rates could be locally enhanced with thunderstorms, leading to the possibility of very heavy rainfall and dangerous flash flooding,” the BOM said.

“At this stage, the widespread heavy rainfall is expected to ease late Tuesday or early Wednesday.

“Thunderstorms may still produce localised heavy falls that may lead to flash flooding during Wednesday.”

Byron Bay’s famous beaches could be severely eroded. Picture: ABC

The BOM also warned damaging winds averaging 60-70km/h were likely along NSW’s coastal fringe from Yamba to as far south as Crescent Head on Monday.

Waves possibly exceeding five metres in the surf zone could also be expected from Yamba to Port Macquarie.

Queensland wild weather

Mother Nature gets up close and personal at Woody Point, Queensland. Photo: ABC

Southeast Queensland’s wild weather has been compared to a category one cyclone, with galeforce winds, damaging surf and record rainfall in pockets.

A surface trough was expected to deepen off the southeast Queensland coast on either Sunday night or Monday morning, the BOM said.

“I am told by the bureau that whilst this is not a cyclone many of the impacts from this weather event will be similar to a category one cyclone event,” Emergency Services minister Mark Ryan said.

“It’ll be the equivalent of an east coast low.”

The BOM issued warnings for the Gold Coast, Brisbane, Moreton Island, North Stradbroke Island, Sunshine Coast, Fraser Island, Caboolture, Cleveland, Redcliffe, Jimboomba, Beaudesert and Springbrook.

It also issued a minor flood warning for the Logan and Albert rivers.

“The rains are here and they are coming significantly and in a heavy severe way … similar to a category one cyclone event,” Mr Ryan said on Sunday.

All Gold Coast beaches were closed on Sunday, along with the majority of Sunshine Coast beaches.

-with AAP