The renovations, expected to start in December next year, are likely to take about 12 months, forcing local and district court matters elsewhere.

Chief Magistrate Judge Graeme Henson wrote to the Law Society of NSW earlier this month about the closure, saying Wollongong Local Court matters would be relisted at Port Kembla, Kiama, Albion Park and Sutherland.

MORE: Court to get $15m facelift

The Mercury understands district court matters will be heard in Campbelltown.

Wollongong and District Law Society president David Potts has slammed the decision, saying a partial closure would have been a better option.

"Although the renovations will take longer, the inconvenience to the community would likely be reduced," he said.

"Our concern is that this closure will make it very difficult for many people in the area; it's likely that thousands of people will be affected [including] parties to proceedings, witnesses and the police."

A spokesman for the Attorney-General's Department said closing the court was the least disruptive option: "Conducting court sittings at a noisy and dusty construction site is not an option and would cause significant delays to the completion of the project."

Mr Potts said the society was particularly concerned about defendants in custody, as it understood there were limited cell facilities at other courts in the region.

The Attorney-General's Department spokesperson said it would look at making greater use of audio-visual link-ups.

The $17-million renovations will include the addition of a new registry, an upgrade to the courthouse entrance, a new call over court and improved jury assembly and deliberation rooms.