Cyclone Alfred: Landfall could be delayed as it slows

Millions of Queensland and New South Wales residents are in for a longer wait as Cyclone Alfred slows down as it tracks towards the coast.

The Bureau of Meteorology (BOM) said the unpredictable system may not make landfall until late Friday or early Saturday depending on how it moves near Moreton Bay. However, there is still a big risk it could make contact from Friday morning.

This means another 24-48 hours of uncertainty for residents in its path and authorities continue to warn people to stay prepared and not let their guards down.

Right now, Alfred is a Category 2 storm, but it could strengthen to a Category 3 before it makes its forecast landfall between Maroochydore and Coolangatta.

Brisbane Lord Mayor Adrian Schrinner said flood modelling suggested 20,000 properties could be impacted by storm surge or flooding.

"According to the modelling, areas most at risk include Nudgee Beach, Brighton, Windsor, Ashgrove, Morningside and Rocklea."

Storm surges of up to one metre higher than usual tides have prompted evacuations in coastal areas, schools across the state have been closed and public transport services have been suspended.

New South Wales to the south is also bracing for impact with Premier Chris Minns warning the number of homes affected could be similar to 2022 flooding in Lismore.

NSW Emergency Services commissioner Mike Wassing said the state was dealing with "three natural disasters in one — gale force winds, rainfall, and flooding".

The BOM expected moderate to major flooding from the Queensland border down to the Manning River, although the river itself is not expected to flood.

Prime Minister Anthony Albanese said the Australian Defence Force were on standby to assist with evacuations and disaster response.

"A Sikorsky S-61L has been deployed to Coffs Harbour. The UH-60 Black Hawk will be prepositioned in Bundaberg in coming days. We have activated the Australian government disaster response plan, a crisis coordination team and deployed liaison officers."

Treasurer Jim Chalmers said "billions of dollars" of damage was expected to be done by Cyclone Alfred.

"There’s a lot of people in harm’s way here. We’re talking about something like four and a half million Australians, potentially in harm's way, 1.8m homes."

Air New Zealand has cancelled all flights in and out of Brisbane on Thursday and all flights in and out of the Gold Coast until Friday," chief operational integrity and safety officer Captain David Morgan said.

"At this stage, it is too early to determine when flights will resume, but services will only restart when it is safe to do so, when roads and rail connections to the airports have reopened, and when it is safe for our people and customers to get to the airport."

Morgan advised customers not to travel to the airport and that those impacted had been contacted directly with rebooking options.

"We understand some customers may no longer wish to travel to or from areas affected by the cyclone, so we are offering additional flexibility for affected customers."

Jetstar has also suspended some routes.