We're being warned Tropical Cyclone Oma will be close enough in the coming days to produce direct impacts along the Queensland and New South Wales coast.

Although it's no longer expected to make landfall, the Bureau of Meteorology says the system is still likely to bring bad weather along the coast.

Here's what we know so far.

Where will it hit?

Cyclone Oma is currently a category two storm and is expected to remain so for days as it tracks towards Queensland. ( Supplied: Bureau of Meteorology )

At the moment the BOM does not expect Oma to make landfall.

Instead it's forecast to slow on Saturday before moving north, parallel to the Queensland coast.

"Although Oma is not expected to make landfall in the coming days, it will be close enough to produce direct impacts along the Queensland and New South Wales coast," BOM said.

What areas has the BOM issued warnings for?

High tide at Brisbane's Breakfast Creek on Wednesday morning. ( ABC News: Tim Swanston )

A cyclone watch has been issued for a large stretch of Australia's east coast, from Bundaberg in Queensland to Ballina in New South Wales.

A severe weather warning is in place for abnormally high tides and dangerous surf from the town of 1770 to Coolangatta.

BOM said the dangerous surf conditions would likely affect Fraser Island and the coast north of Bargara from this afternoon and evening, and the remaining south-east Queensland coast and northern New South Wales overnight into Friday.

All Gold Coast beaches and a number of Sunshine Coast beaches have now been closed.

So how bad is this going to be?

The BOM expects to issue tropical cyclone watches "within the next 24 hours". ( Supplied: RAMSDIS )

The BOM said the system is likely to bring heavy rain, gale force winds, dangerous surf and abnormally high tides across the watch area.

For most cyclones, the most severe winds are confined to a small area around the outside of the eye, according to the BOM.

So the coastal area may escape the worst of the bad winds but BOM forecaster Michael Knepp said south-east Queensland could still see it start picking up.

"We're going to see gale-force winds developing tomorrow, and not only gale-force winds but conditions along the beach are going to be quite dangerous," he said.

But along with the strong winds, cyclones can bring other dangers like heavy rain and flooding as well as storm surges.

In the case of heavy rainfall, it can get quite bad if the storm is travelling slowly or if it stops over one area.

What category is Cyclone Oma?

Cyclone categories are based on wind speed, the faster the winds the higher the category. ( ABC Weather: Kate Doyle )

It has been downgraded from a category three to a category two system.

Basically, the system is a way of assessing the strength of a cyclone. In Australia, category five cyclones are the strongest, bringing the most destructive winds.

A category two system is considered to bring "destructive winds" with typical gusts over open flat land of 125-164 kilometres per hour.

If you want to know more, the Bureau of Meteorology has pulled together this useful list of tropical cyclone severity:

Category Wind gusts Ocean swells Damage 1 Up to 125kph

(Gales) 1.2-1.6m Negligible house damage. Damage to some crops, trees and caravans. 2 126-164kph

(Destructive) 1.7-2.5m Minor house damage. Significant damage to signs, trees and caravans. Heavy damage to some crops. 3 165-224kph

(Very destructive) 2.6-3.7m Some roof and structural damage. Some caravans destroyed. Power failures likely. 4 225-279kph

(Very destructive) 3.8-5.4m Significant roofing and structural damage. Airborne debris, widespread power failure. 5 Winds above 280kph

(Very destructive) More than 5.5m Extremely dangerous with widespread destruction. Houses flattened, cars overturned.





And what damage is the cyclone causing so far?

A 4WD was submerged at Midge Point north of Mackay when the area was impacted by the king tide on Tuesday. ( Supplied )

In New Caledonia, it has caused some coastal damage and flooding, while in Queensland some areas are already experiencing dangerous surf conditions, large swells and abnormally high tides.

The BOM have already issued a hazardous surf warning, including for the Fraser Island and Capricornia areas on Thursday.

"We have already seen the surf start to pick up, but we do expect that to continue to increase in coming days as Oma comes closer and more swell is brought towards the south-east," Ms Pattie said.

"This is for areas between 1770 and the New South Wales border. We can expect to see waves of 4-6 metres on some of the beaches as well."

Beach erosion, which has already occurred north of Mackay at Midge Point and the Pioneer River, is likely to continue with the hazardous marine conditions.

And Gold Coast lifeguards are expected to close beaches as the swell increases.