A tropical cyclone watch is now in place covering the coast from Bundaberg in Queensland to Ballina in northern NSW.

Beaches have been closed and sand bags filled as the category 2 system tracks towards south-east Queensland.

All 34 Gold Coast beaches have been closed for the next three days as forecasters predict up to 300 millimetres of rain.

Further north, the Sunshine Coast council is "preparing for the worst" before rain is expected to flood low-lying streets and gale-force winds pull down power lines.

Emergency management coordinator Cathy Buck said the council was in touch with beachside caravan parks in case of tide surges.

“We are looking at possibly moving, not evacuating at this stage, but moving the people who are very close to the shorelines back from there,” she said.

"It's a very ambiguous system. We still don't have a definite pattern of it. We prepare for the worst-case scenario and hope for the best.

"It changes basically by the hour however at this stage we're just trying to keep abreast and make sure we are prepared for any circumstances.”

Ms Buck said the Sunshine Coast was expecting about 150 millimetres of rain each day from Friday to Monday.

“At the moment our river systems are quite low so they can withstand that but they are looking at isolated heavy falls so we are being very careful of what people are doing in those particular low-lying areas," she said.

A do-it-yourself sandbagging station was set to open at the Nambour Showgrounds on Thursday afternoon.

Cyclone Oma is expected to move towards the coast during Friday and Saturday while moving north and staying offshore, but she may make landfall.

"Forecast certainty is shaping up to see the most likely scenario that Cyclone Oma will approach the coast this weekend, and a coastal crossing cannot be ruled out at this stage,” Bureau of Meteorology state manager Bruce Gunn said.

"Surf and swell conditions will be hazardous for coastal activities such as rock fishing, boating, and swimming and many beaches are already closed for public safety.”

Fishing boats along the coast have returned to port in preparation for the wild weather, but a retreat from the sea may not be such a bad thing.

Mooloolah River Fisheries general manager Ash Wall said torrential rain and gale-force winds could be good news for the Sunshine Coast’s prawn industry.

“In actual fact it will give the fishing ground a rest and agitated water helps bring feed for prawns so it will help prawn growth,” he said.

“If you get a drought on the land you get a drought at sea basically so it needs rain to flush the river systems out to bring prawns out into the ocean and agitate the feed.

“Wind and agitation is good for them.”

Events along the Queensland coast are being cancelled and holidaymakers are rescheduling travel plans as dangerous conditions are expected to continue into early next week.

Brisbane man Henrik Vesander said he has been left in the lurch by a Moreton Island ferry operator who has refused to let passengers re-book their trip, despite the impending cyclone.

“I find it really unbelievable and disappointing. Our accommodation provider has given us credit to re-book at another time but the ferry will not. We are not requesting a refund we just want to re-book," he said.

A Moreton Island Adventures booking expert said customers have had “plenty of time” to change travel plans before Cyclone Oma arrived.

“Customers agree to terms and conditions when they book. They must give a minimum five days notice and they have had plenty of time to be aware of that [cyclone] and time to prepare,” a Moreton Island Adventures booking expert said.

But Mr Vesander said severe warnings had only been issued in the past 24 hours.

"We contacted them as soon as we were able to after weather warnings, we have been watching forecast the whole time," he said.

Queensland Premier Annastacia Palaszczuk said preparations had begun with relevant mayors and it was likely there would be a Queensland Disaster Management Committee meeting on Friday morning.

"The problem at the moment is that although it's sitting off the Queensland coast, the Bureau of Meteorology cannot put a direct path that it will take," she said.

"It's a cyclone. They are unpredictable and we do know that there could be waves between five and seven metres, I'm being told."

- with Toby Crockford