Illawarra Shoalhaven

Biosecurity -IDWA

Biosecurity - Illawarra District Weeds Authority

The Illawarra District Weeds Authority was originally established by Wollongong, Shellharbour and Kiama Councils in 1993 and is now a business unit of the Illawarra Shoalhaven Joint Organisation. 

The IDWA has delegated authority from Wollongong, Shellharbour and Kiama Councils to carry out local control authority functions under the Biosecurity Act 2015.  It also represents those councils on the South East Regional Weeds Committee.

The Regional Weeds Committee is tasked with implementing the Regional Strategic Weed Management Plan.  Details of this Plan may be found on the Local Land Services website. 

As the Local Control Authority for weeds under the NSW Biosecurity Act 2015 the IDWA has the following functions over the land in which it operates:

-the preventions, elimination, minimisation and management of the biosecurity risk posed or likely to be posed by weeds

-to develop, implement, coordinate and review weed control programs

– to inspect land in conjunction with its weed control functions

-to keep records about the exercise of the local control authority’s functions under this Act

-to report to the Secretary about the exercise of the local control authority’s functions under this Act.


The primary role of the IDWA is provide a framework for dealing with  weed biosecurity risk in the community and ensure compliance with legislation. This involves the enforcement of the general Biosecurity Duty of landholders and occupiers in the Authority’s area of operation and the control of priority and high risk new and invasive weeds on Council lands.


A copy of the Biosecurity Act 2015 is also available. 

The Department of Primary Industries (DPI) has available a Weed Control Handbook, available for download, and the Weed Wise site, which is helpful in identifying weeds. 

CWO removing the highly invasice Prohibited Matter plant - Parthenium weed. Illawarra - February 2021

Weed Biosecurity and Control

Broadly speaking a ‘weed’ is best defined as a plant growing out of place or where it is not wanted.  Most of the serious weeds in Australia have been introduced from overseas.  Plants such as rhus tree can cause serious health problems including asthma, allergies and dermatitis.  Blackberry and giant parramatta grass threaten productive agricultural lands whilst pampas grass, cat’s claw creeper, bitou bush and boneseed pose a major risk to our natural environment.  Aquatic plants such as water hyacinth, salvinia and alligator weed are a major threat to our freshwater wetlands, rivers and water storage systems.

Weeds cost the Australian community some $4 billion annually.  Over two-thirds (66%) were introduced legally as attractive garden ornamentals.  Every year at least 12 new species become naturalized somewhere in Australia.  Of these at least four become significant or major weeds.  Although often considered attractive many of these plants produce large quantities of berries or seeds.  They subsequently spread uncontrolled into neighbouring land, often carried by birds or the wind, where they quickly establish at the expense of existing vegetation.  There are many ways to control invasive weeds and total eradication usually requires a concerted effort over a long period of time.  Methods of control include physical or mechanical removal, the use of herbicides and in some situations biological control agents.  Once the weeds have been controlled it is essential to replace them with desirable species to provide competition.

What is a Priority Weed?


The Southeast Regional Strategic Weed Management Plan 2023-2027 supports regional implementation of the NSW Biosecurity Act 2015. This plan identifies the state and regionally prioritised weeds for the south east region including the Illawarra. Under the Biosecurity Act 2015 there is no scheduled “list” of weeds although a range of weed species have been prioritised at the State and Regional level.

Listed below are the priority weeds for the Illawarra District Weeds Authority (IDWA) area of operation. The plants shown in the following tables are listed as State or Regional Priority Weeds throughout the local government areas of Kiama, Shellharbour City and Wollongong City. For more detailed information click on the name of the weed and you will be re-directed to the DPI NSW WeedWise site. 


Biosecurity News

Reports, Papers & Policies