Damage from April floods may not be known for years: council

The report also stated there was 3400 tonnes of waste collected from more than 1400 free kerbside collections.

An update on the flood recovery has been tabled at Monday's city council meeting, which recommends councillors approve efforts to seek state government money to repair or replace stormwater infrastructure.

"The initial and ongoing geotechnical instability is a significant concern at known and new sites where the storm resulted in extensive movement with the risk of further instability," the report stated.

"It is not expected that the full extent of damage to the (underground) stormwater system will be known for several years until CCTV is used to survey stormwater pits and pipes."

A review of creek, culvert, basin and dams found 88 kilometres of creek length affected by debris washed down from the overflow, across 40 suburbs.

"Across the LGA there are 30-plus creeks and watercourses which are on private and publicly-owned property as well as 112 basins and dams," the report stated.

"Elements of our stormwater network are either impaired or operating with limited capacity.

"There are large volumes of material and debris that are in or on creek banks on private property that presents high risk to council essential infrastructure, potentially resulting in further flood impacts for residents and businesses."

The report noted there had been six disaster declarations in the city since joint Australian and state government disaster recovery funding arrangements were introduced in 2018.

To reduce further declarations occurring, the report said a different approach was needed to overcome the disaster recovery funding arrangement limitations, which only allowed for like-for-like replacements of stormwater infrastructure and limited any emergency work on private property.

"There is a need for investment in the enhancement (betterment) of infrastructure that would reduce the risk of it being impacted in the same way for similar natural disasters in the future," the report stated.

It recommended the council work with the state government on a Wollongong-specific plan, which would include funding for upgraded stormwater infrastructure.

"This will enable council to mitigate some of the risks associated with future storm events including funding for the repair and renewal of infrastructure and the collection and disposal of debris on private property that presents potential further and broader risk to life and property," the report stated.