TfNSW advice says that with Thirroul traffic already congested, this development could make it significantly worse.

"TfNSW believes the development, in its current form, will significantly increase congestion in Thirroul and create a number of road safety issues," Transport's advice to Wollongong City Council said.

TfNSW criticised the traffic estimates, saying it was done on days that "may not be representative of peak conditions" on Lawrence Hargrave Dr. It compared the developer's consultant's figures against signal data from February, March, May and September and found the days surveyed in September were "lower than other weekday and Saturday peaks".

This would mean a calculation of traffic increase would be skewed lower.

Sunday was in fact the busiest peak. TfNSW said the analysis should be "amended" to consider these factors.

Wollongong City Council has called for a significant re-design, saying the Visual Impact Assessment (VIA) was "misleading" about the building's relationship to height limits. There had been "no consideration" given to the direct impacts of viewing from the footpaths directly opposite the site, so the VIA should be done again from sites that gave an accurate impression of the visual impact at street level.

Council's planner's report also said the development was "unsatisfactory" on heritage grounds, and the plans should be changed to "break down the horizontal form and bulk" of the building's frontage, allowing better views to the escarpment.

It called for a traffic assessment of the impact on nearby Redman Ave, and raised concerns about a proposed car park exhaust outlet to the neighbouring WF Jackson Park.

These problems meant the plans would have to be re-notified for public exhibition once the additional information had been provided.

The Mercury put these concerns to Thirroul Plaza Pty Ltd. Spokeswoman Emma Foster said: "There are ongoing discussions with Transport for NSW and Wollongong City Council regarding the Thirroul Plaza DA, the developers are meeting with Transport for NSW, as per their request."

Council also requested substantial extra information about stormwater and flood assessment.

The advice is contained in a document sent to the developer's designer Loucas Architects, obtained by a resident under a Government Information (Public Access) request, and seen by the Mercury.

The developers behind the plans are Austinmer engineer Angelo Forte of Mainland Civil, Austinmer builder Mark Forte of Genesis constructions, and investment partners from Sydney and Queensland.