"In my tent, it is basically just a waterbed."

Splendour In The Grass festival goer Kadence Mathers spent the night making sure her tent wasn't going to flood after more rainfall hit the already drenched event.

The music festival is set to continue being mayhem in the mud on Saturday as organisers push ahead despite the weather chaos.

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Mathers said the campsite is "grim" and she and her friends want to leave but their cars are blocked in and bogged.

"Last night it was just a steady stream of rain, and so everything is way more flooded now," she said.

"I've been using socks and stuff to try and mop up the water that is coming in."

"Unless they cancel the entire event we can't get out.

"Even if they do cancel the entire event the car we came in is, like the tyres are almost underwater, it's going to be bogged."

But some blue sky is peeking through at Byron Bay in northern New South Wales providing hope for festival goers that the event will go ahead today.

"It is meant to clear up, so it shouldn't be too bad," a festival goer said.

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On Friday, festival-goers donned ponchos and had to trek through fields that resembled swamps in Byron Bay, only for the first day of the event to be officially washed out.

It wasn't all bad news for day one, with some of the music acts heading to local venues in Byron Bay to perform for disappointed attendees.

Surprise performances from Baker Boy, Confidence Man and Yungblud went ahead at the Beach Hotel on Friday night.

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Organisers had said their decision to cancel Friday's performances on the main stages was due to "a significant weather system" and they had "decided to err on the side of caution".

Work was being done "on repairs", organisers said, adding: "We look forward to Saturday and Sunday programming moving ahead as planned."

The already sodden event ground – where camp fields have become quagmires – is expected to get a top-up on Saturday, though it's unlikely to dampen the spirits of most festival attendees.

Weather set to brighten but mud to remain

The Bureau of Meteorology predicts a 90 per cent chance of rain, between 4 and 6mm, around the North Byron Parklands in Yelgun, although the offshore low bringing the wet weather is moving away from the coast, easing showers over north-east NSW and south-east Queensland.

(See full list of current NSW weather warnings here)

There are also severe weather warnings in place for damaging surf, with "large and powerful surf conditions expected to be hazardous" as the low pressure system lingers offshore.

Weatherzone says "wind should ease from Saturday morning" across the region as the low moves offshore.

The large swell will stick around on Saturday, before easing from Sunday.

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Highs of 18C are forecast for Saturday in the Byron Bay area with overnight temperatures falling to between 9C and 12C before picking back up on Sunday, when the mercury could reach 20C.

Moist onshore winds and showers are on the forecast for the rest of the NSW coast.