By Savannah Meacham in Brisbane

People have been warned to leave or prepare for the worst, with a tropical cyclone on track to cross a densely populated part of Australia’s coast for the first time in 50 years.

Tropical Cyclone Alfred is looming off Queensland’s coast, threatening to bring heavy rainfall, damaging winds and monster waves.

It is forecast to cross between Queensland’s K’gari (formerly Fraser Island) and the Gold Coast on Thursday or Friday as a category one or two system.

It will mark the first time since 1974 Queensland’s southeast has taken a direct hit from a cyclone.

The crossing location is more likely to be near Brisbane with towns south of the city at risk of the most serious rain and wind conditions.

Island communities east of Brisbane are warned to leave now or be prepared to ride out the storm.

“There will come a point where it’ll be too late to leave those islands,” State Disaster Coordinator Shane Chelepy told reporters on Monday.

Ferry and barge services may cease to islands in the next 24 to 36 hours.

Generators, health professionals and emergency services are set to be deployed to the islands.

Emergency services have urged anyone living on house boats to consider evacuating while low lying or coastal southeast communities should begin sandbagging before heavy rainfall begins.

Shipping operations at the Sunshine Coast’s Mooloolaba have stopped until Alfred passes.

Two cruise ships are looking for alternate ports to dock while another will land at Brisbane to offload passengers.

Schools remain open but Queensland Premier David Crisafulli warned there was a “very strong” likelihood they may close when Alfred crosses the coast.

“This is certainly an event that doesn’t happen a lot for this part of the state, but it isn’t unprecedented and I am asking Queenslanders to be ready for it,” he said.

The last cyclone to cross the southeast Queensland coast was Zoe in 1974 while Nancy came close in 1990.

Alfred is a category one system in the Coral Sea, about 450km northeast of Brisbane.

It is “yo-yoing” between a category one and two system as it travels about 20km/h south east.

The system is expected to slow and do a U-turn towards the Queensland coast on Tuesday before making landfall later in the week.

Winds at the centre of the cyclone are 95 km/h with gusts of up to 130 km/h.

Alfred is already impacting the coast causing waves up to 15 metres, leading to significant erosion from K’gari to the Gold Coast.

Marine Rescue Queensland has urged boaties to stay home and not go fishing while the system sweeps through.

The cyclone watch area spans from K’gari to Grafton, NSW for heavy rain, damaging wind and monster waves.

NSW’s Northern Rivers is only just getting back on its feet after flooding three years ago that claimed five lives and destroyed homes.

NSW Emergency Services Minister Jihad Dib assured locals authorities were doing “everything we can” to prepare for the looming system.

“We’re cognisant of what the Northern Rivers have gone through and some of the trauma that they carry,” he said.