Welcome to the Illawarra District Weeds Authority (IDWA) site.

The Illawarra District Weeds Authority (the IDWA) was formed in 1993 by Wollongong, Shellharbour and Kiama Councils to administer the Biosecurity Act 2015 and to control priority weeds within the three local government areas.

The IDWA has been a formal business unit of the ISJO since 2019 with the ISJO acting as its Manager and Secretariat.  The IDWA is an agreed regional service delivery under the ISJO Charter.

The IDWA represents our councils on the South East Regional Weeds Committee that is tasked with implementing the Regional Strategic Weed Management Plan. 

Further information on this Plan can 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 prevention, 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.

It undertakes these functions by controlling priority and invasive weeds on all council owned lands including certain roadsides and Crown land through special grants.  In addition it is responsible for the inspection of private and public property for priority and invasive weeds and the giving of directions and advice to landholders or occupiers so that adequate control is maintained.

Priority weeds and their control

If you own, occupy or manage land in the Illawarra you have a responsibility known as the General Biosecurity Duty (GBD) and your role as a landholder under the Biosecurity Act 2015 is to prevent, eliminate or minimise weeds and their impact on the environment.

For a more detailed explanation a video can be found here.

A copy of the Biosecurity Act 2015 is also available. 

In addition, the Department of Primary Industries (DPI) has available a Weed Control Handbook and the Weed Wise website to assist in the identification of weeds. 

Our website

The IDWA website has been designed to provide guidance on the identification and control of Priority weeds within the Illawarra region of southern New South Wales.

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%) of our problem weeds were introduced legally as attractive garden ornamentals and 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 that subsequently spread uncontrolled into neighbouring land.  They are often carried by birds or the wind and 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.

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.