Tropical Cyclone Alfred's "erratic movement" has pushed back its forecast landfall, with a crossing now expected in the early hours of Saturday.

It's currently 280 kilometres east of Brisbane, moving west at 10 kilometres an hour, and is still expected to cross between Maroochydore on the Sunshine Coast, and Coolangatta on the Gold Coast as a category two system.

Predictions on Thursday morning had put Alfred crossing in the early hours of Friday morning, and before that, at high tide in the middle of Thursday night.

"Overnight Tropical Cyclone Alfred briefly doubled back on its path. It's current movement has resumed that westward track towards the coast," Bureau of Meteorology's (BOM) Matthew Collopy said.

"This erratic movement has resulted in a delay in the forecast crossing.

"It approaches the outer islands very late on Friday and is then expected to cross the coast in the early hours of Saturday."

Mr Collopy said the storm surge could push sea levels half a metre to one metre above "the normal highest astronomical tides" possible.

A 12.3-metre wave was recorded off Main Beach overnight — the highest ever recorded.

"If the system crosses at high tide, there is the risk of seeing storm surges up to 1.5 metres, particularly around the Redland Bay area and the Gold Coast," he says.

Heavy to locally intense rainfall is expected across the south-east from later on Thursday to "at least Saturday", with possible rainfall totals of more than 800 millimetres.

Queensland Premier David Crisafulli said there's a "real risk of inundation in those storm tide areas", particularly if the cyclone crosses at high tide.

"Many Queenslanders in the south-east are aware of this, they have experience in this and have handled it very well over the years.

"It's important that you develop your plan now if you are in one of these zones."

Public transport services and elective surgeries are suspended Thursday and Friday, and schools and childcare centres are also closed, with more updates to come.

Some supermarkets in the south-east will close from Thursday, with others reducing their hours.

Mr Crisafulli said these decisions were being made case-by-case.

Major roads and bridges may also be closed if winds intensify, but Mr Crisafulli said they would be kept open for "as long as we can" for key workers.

Delays could make system more intense

Earlier, Prime Minister Anthony Albanese said Alfred's delay was "not all good news" with the possibility the system would intensify as it crosses.

"It is still anticipated this will … reach landfall, it will just do it later," he said.

"And a risk of course is that slowing up, it increases in its intensity."

Mr Albanese said he would immediately sign off on a request for early recovery grants for affected councils, and that the ADF stood ready to help.

The current warning zone extends from Double Island Point in Queensland to Grafton in New South Wales, including Brisbane, the Gold Coast, Sunshine Coast, Byron Bay and Ballina.

Brisbane City Council issued a "prepare to evacuate" call to action for areas within the possible storm surge zone on Wednesday afternoon.

There is also a "prepare to take shelter" call to action for the rest of Brisbane and Moreton Island. Sunshine Coast and Scenic Rim Councils have been told to "prepare now", while Logan is being told to "prepare to take shelter".

Modelling shows almost 20,000 properties in Brisbane and 6,000 on the Gold Coast are at risk of storm surge or flooding.

Queensland Advocacy for Inclusion has set up a hotline for people with disabilities ahead of Alfred's landfall.

CEO Matilda Alexander said it was "absolutely an anxious time" for people with disabilities.

"We're asking people to think about how they're going to communicate in a disaster," she told ABC News Breakfast.

"How do you usually receive your information? Do you need to write down some instructions in case there's a rapid transition of staff or carers? Who needs to know your emergency plans?

"We're also asking people to think about two different kinds of plans. One if you need to evacuate and the other if you need to stay in place for a week or so."

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