A spokeswoman said there will be increased rain, wind and waves on Tuesday morning but said conditions would ease "at some point."
"The expectation at the moment is later in the day. But, certainly, [Tuesday] morning we'd be expecting some increased rain, wind and waves. The surf does look like it'll hang around for a bit longer now."
The BOM's Queensland branch issued a flood watch and severe weather warning from Fraser Island to the Queensland-NSW border, warning of river level rises and minor flooding.
"The Logan, Albert and south coast River catchment areas are now saturated with renewed river level rises expected with forecast rainfall," it said. "Storms are expected throughout the flood watch area during Monday and into Tuesday."
In NSW heavy rainfall was expected to intensify on Monday evening before easing late Tuesday or early Wednesday.
Heavy rainfall is expected in the mid-north coast along with thunderstorms, flash flooding, damaging winds and surf and abnormally high tides that could lead to "significant" beach erosion north of the Ballina area, the BOM said.
BYRON'S MAIN BEACH 'SWALLOWED'
The coastline has been pummelled by gale-force winds and extreme high tides in the last few days, leading to over 900 requests for assistance over the course of the savage weather event. Karlene York from the SES said "most of the jobs we're assisting with are fallen trees, leaking roofs and windows".
As the areas prepare for another day of up 104km/h winds which were recorded in Cape Byron Monday morning, social media has been filled with images of damage inflicted in the 1000km danger zone.
Byron Bay saw 6m waves and abnormally high tides. Byron Shire Mayor Simon Richardson told Sky News he hopes the main beach will be able to recover.
"It's a beach that we all hold really dear," he said. "We've had quite a lot of erosion events leading up to this previously and obviously we've got another big king tide tomorrow and some more gnarly weather so hopefully we all batten down the hatches and so does this particular area and when the water recedes the beach can begin to restore itself."
Richardson called for locals and tourists to be responsible and remain safe by not driving on flooded roads.
"Along the coast the waves have been huge, we're looking up to five metre waves, we've got large swells, crazy water, we've also got king tides and really high water levels smashing along the whole coast," he said.
Queensland Police shared photos of a "serious landslide" in Mount Tamborine that showed huge boulders that had closed Tamborine Mountain Rd, locally known as the goat track.
"Now that's a big rock," one post read, showing a police officer beside a giant boulder.
A jaw-dropping video of First Bay Coolum's usually pristine beach completely encased in thick mounts of murky white foam also captivated social media, showing the lathery white substance wobbling on top of the water in the aftermath of the brutal weather.
Sunshine Coast Daily shared a video of water surging over a spillway at Wappa Dam which was currently sitting at nearly 110 per cent capacity with more rain expected.
Thousands were left without power in many areas with police closing roads as debris falls from buildings and trees.
