The proposal is to amend plans approved by Wollongong City Council in 2017, on flood prone land at Newton Park immediately adjacent to Kembla Grange racecourse.

The number of residential blocks - mostly for retirees - would come down to 150 so the size of each block would increase, now ranging from 198 to 310 sq m (up from the 133-231sq m blocks approved previously).

Read more: Construction commences on new Bunnings Kembla Grange

The developer wants to use coal wash reject material to build up the site, but council had imposed a condition that only "virgin excavated natural material" be used.

The applicant's consultant, Cardno, calls the development a "manufactured home estate", and said these changes were sought as a result of "extensive market research".

The development plans, submitted for Cartier Holdings Pty Ltd, also include an updated flood study and a flood evacuation plan.

Most of the site had been identified as "high risk" for flooding, which was described as a "significant challenge" for the estate. Much of it would be underwater by metres in a major rain event, this flood study shows.

The developer plans to use bulk earthworks to elevate the site so that it would be higher than the level of a significant flood - from a once in 100 years rain event. This would reduce the habitable area to a medium or low flood risk, the study says. Homes would still be inundated in the event of the Probable Maximum Flood - a severe storm with severe flooding.

Cardno is asking the council to remove a ban on using coal wash reject (CWR) material for these earthworks. This would include sorting and crushing on-site.

"The operation (particularly any sorting and crushing) would be strategically located away from the site boundary and in particular away from residential properties to reduce noise or dust issues," its application says.

"CWR has been approved by council and widely utilised within developments in the Illawarra region.

"CWR is a high-grade fill material ideal for select fill, bulk fill, sub-grade and drainage layers. CWR is classified as inert waste under the EPA Waste Guidelines and previous research and practical applications within the Wollongong LGA have proven that it is a viable and acceptable fill material for residential developments."