Children's advocacy and aid charity Unicef says there is a need for child-sensitive disaster preparedness, response and recovery plans.
The organisation has been helping to assess the needs of children caught up in catastrophic flooding in parts of New South Wales and Queensland in February and March last year.
It carried out interviews with key informants like educators, across 20 communities affected by the floods.
There were 22 deaths during the events, and like Cyclone Gabrielle last month in New Zealand, the severity and speed of the flood meant many people were caught with little time to evacuate leading to roof top rescues.
Thousands of young Australian children now need ongoing intensive mental health support following the disruption and upheaval.
In New Zealand children are also recovering from the trauma of losing, homes, pets, favourite toys and the distress of witnessing the physical threats flooding brings with it.
The Extreme Weather Recovery Committee, chaired by Minister for Cyclone Recovery Grant Robertson and the Cyclone Gabrielle Recovery Taskforce, chaired by Sir Brian Roche, are currently looking at how best affected communities can be supported as part of their work.
Unicef's chief advocate for children and director of Australian programmes, Nicole Breeze, told Checkpoint children had unique and distinct needs that must be taken into consideration when offering support and planning for the future.
She said it was important children got the right support at the right time.
"We need to make sure that our systems get stronger and that children's needs are dealt with from day one" - Unicef's Nicole Breeze
"Sometimes we make the mistake to think that children are just the same as small adults, and that when we plan policy, when we plan investment, if we plan for adults, this will work for children.
"But we know that that's not the case. Here in Australia, nobody does this intentionally, but sometimes children's needs are overlooked.
"So what we're saying to our own authorities, and it may be relevant across there [in New Zealand] is that we actually need child's sensitive disaster preparedness, response and recovery plans. We can't leave this to chance.
"We need to make sure that our systems get stronger and that children's needs are dealt with from day one."
Distress in children may not manifest for a considerable period of time and an assumption can be made that they are fine, she warned.
"The view will often be the kids are doing fine - they're robust, they're resilient, the adults around them are the ones sort of front facing all of the stress all of the issues and all of the challenges.
"The research shows that sometimes the impacts stay hidden for a year, two years or even longer. And we've recently, five months after the floods on the southeast coast of Australia, our teams conducted a needs assessment. And it was really telling us in terms of what some of these key challenges are."
Those teams talked to educators and teachers, who reported a range of unique issues particular to children and families. Absenteeism in schools increased, even five months after the initiative events and immediate disruption to education.
Other issues were reported, from exposure to health dangers like toxic mould to the loss of recreational and play spaces.
But the most importantly, there were changes related to mental health and wellbeing. Most tellingly, absenteeism increased with the rain, Breeze said.
"I think it's really the anxiety levels that peak and that's what our interviewees were telling us - a clear pattern of heightened anxiety, evidenced amongst children five months after these events.
"When it rains, children really exhibiting high signs of anxiety and we heard the same actually with the bush fires here in Australia as well - when when a fire truck passed to school area, heightened anxiety."
Children also showed signs of grief, because of lost homes, beloved pets and favourite toys. Educators reported some regression in skills in the two-to-four age group, which were associated with what the children had experienced.
"For example, children who had previously been able to use the toilet without a parent's assistance were showing some signs of regression. I mean, previously acquired skills, and for older children aged five to 12 lots of reports sadly, of sleep disturbances, nightmares and other signs of stress," Breeze added.