The state government's draft plan sets a target of an additional 45,000 dwellings for the Illawarra region by 2031.

Its release again raises concerns the southern boundary of Gerringong could be further expanded into farmland.

In 2011, fears overdevelopment could eventually blur the boundary between Gerringong and Gerroa appeared to be put to rest when then NSW Planning Minister Brad Hazzard signed off on the latest Kiama Local Environmental Plan.

However, the government's latest draft planning document has identified south Gerringong as a potential greenfield area.

"We will work with Kiama council to review the potential of these areas, and to identify an appropriate boundary for the southern expansion of Gerringong, noting the importance of maintaining Gerringong and Gerroa as separate urban areas," the document said.

Kiama Mayor Brian Petschler urged the community to take part in a Department of Planning and Environment forum on the draft plan.

Cr Petschler emphasised how future planning would affect the area.

"The proposed increase in dwellings, the height of buildings, and the southern boundary at Gerringong ... will have an impact on our community.

"Council believes the southern boundary of Gerringong has been agreed in the current Local Environmental Plan and is surprised to see it raised again.

"It is imperative Kiama residents know about these proposed changes and voice their opinion while they have the chance."

The forum will take place at Kiama Leagues Club on Wednesday (today) from 6.30pm.

Meanwhile, a Jamberoo Community Information Night to discuss their concerns with the draft plan will take place on Tuesday, November 25, at Jamberoo Bowling Club.

It will be from 7pm for a 7.30pm start.

There will be guest speakers and information available on the night.