The study, first drafted in 2013, has been reviewed by consultant firm Jacobs Australia, to take into account changes in survey data, the impact of more development in the catchment, and increased vegetation in the Gurungaty waterway from JJ Kelly Park to Port Kembla harbour.

Looking at why Swan St had flooded so regularly in recent years, Jacobs recommended Wollongong City Council consider "vegetation management measures" to improve the flow through the waterway.

The study found while rainfall in the catchment from 2010-17 was high than the average of the previous 10 years, it was no higher than the long-term average.

"The results indicate that for the most part, there have been no long-term changes in rainfall patterns in the study area or across the region in general," Jacobs' study states.

More consequential had been the overgrowth of vegetation in the waterway, and changes in the channel's shape, over recent years.

The results were that the estimated flood level was 100mm-200mm higher than in the 2013 model.

Further analysis of the impact of changes to the shape of the waterway was also recommended.

At Monday night's council meeting it was decided not to vote on accepting the new study.

"Staff have sent out some information suggesting that points raised in the public access have been covered in a general sense in the report, but not specifically - and they'd like to tidy it up to make sure there is some specific reference to points raised," councillor David Brown said.

Central Wollongong is the last of the city's catchment flood studies to be completed. The studies, and plans, were initiated following the devastating floods which hit Wollongong in 1998.