The annual cost of natural catastrophes in Australia will soar from $6.3 billion to $23 billion by 2050 because of population growth and increasingly extreme weather, a new report claims.

A new focus on prevention and mitigation is needed, according to the Australian Business Roundtable for Disaster Resilience and Safer Communities.

The roundtable – comprising the CEOs of the Australian Red Cross, IAG, Investa Property Group, Munich Re, Optus and Westpac Group – was formed last December to champion resilience investment.

It says governments spend $50 million each year on pre-disaster resilience, compared with $560 million on post-disaster relief.

Investing $250 million a year on resilience would cut relief spending by more than half and generate savings of more than $12 billion by 2050.

The group says building more resilient homes in cyclone-prone areas of Queensland would reduce the properties’ risk by 66% and save $3 for every $1 spent.

Raising the wall of NSW’s Warragamba Dam by 23 metres would cut flood costs from $4.1 billion to $1.1 billion by 2050, saving more than $8 for every $1 spent.

Bushfire mitigation in Victoria, including vegetation management, would have a positive cost-benefit ratio of three to one, the group claims.

The report recommends appointing a national resilience adviser and establishing a business and community advisory group.

It says a commitment to long-term funding of pre-disaster resilience is required, with priority given to investment activities that deliver savings.

IAG CEO Mike Wilkins says in the report that governments carrying out mitigation works are “enhancing the economic and personal wellbeing of all Australians, as well as enabling a reduction in insurance premiums for those exposed to natural perils”.