Wollongong City Council has launched a legal challenge against controversial developer Frank Vellar over a proposal that was at the centre of corruption hearings in February.

The Quattro development, on a site bounded by Flinders, Campbell and Keira streets in Wollongong, came under intense scrutiny at the Independent Commission Against Corruption (ICAC) hearings, after it emerged Mr Vellar may have been sleeping with city council planner Beth Morgan.

In sometimes lewd and revealing exchanges, emails showed the two were in contact while the development was being considered in 2004.

The council is now attempting to overturn approval for the site, despite the fact it was approved in 2006.

The proposal, which was passed on August 18, 2006, included 40 units, a restaurant, 18 shops and two commercial suites with parking for 803 cars.

Yesterday, the council confirmed it had launched proceedings against Mr Vellar's development company Sebvell, but would not reveal details of the case.

"At this stage, until such time as the Land and Environment Court proceedings have been finalised and the ICAC commissioner's report has been handed down, it would be inappropriate for council to comment further," a spokeswoman said yesterday.

Mr Vellar is being represented by Wollongong firm Heard McEwan lawyers.

Solicitor Malcolm Heard said it was not appropriate to comment on the case at this stage.