It will take at least 20 years to implement the backlog of flood management works in NSW at the current rate of funding, the Floodplain Management Association (FMA) says.

The state has more than 100 floodplain risk management plans awaiting implementation, but these and resilience initiatives “can be stymied by piecemeal, variable and insufficient funding”, it told the Productivity Commission inquiry into natural disaster funding.

There is “very little, if any, capacity” for funding large-scale or expensive projects such as levees and house buy-backs, yet floods cause about $550 million of damage a year nationally.

A $15.8 million levee for Deniliquin took 12 years to complete but will avoid an estimated $85 million in damage from a one-in-100-year flood.

The FMA wants greater flexibility for councils and other agencies to decide how funding is best spent, and more effort on mitigation.

It says councils do not have the expertise to produce new flood maps and need additional funding to hire specialists, while community engagement and education are also important.