Weed risk assessments frequently asked questions

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How do I know if a species has already been assessed?

Species which have been assessed for importation into Australia are listed as either permitted or not permitted entry on the department's Biosecurity import conditions (BICON) system.
Importers should check BICON prior to importing seed into Australia to find out if the species is permitted and if there are any conditions required for importation. If the species is not listed in BICON, the importer must complete a New Plant Introduction Form and submit it to the department.

Why are some ‘weedy’ species allowed into Australia?

People may consider plant species to be weeds for a number of reasons. If a 'weed' species is already present in Australia, but is not listed as noxious and is not under ‘official control’ it cannot be prohibited entry under Australia's international obligations, regardless of whether it is considered a weed in other situations.
‘Official control’ is defined by the International Plant Protection Convention as ‘the active enforcement of mandatory phytosanitary regulations and the application of mandatory phytosanitary procedures with the objective of eradication or containment of quarantine pests or for the management of regulated non-quarantine pests’ (FAO 2016a).

What information is required to conduct a Weed Risk Assessment?

Conducting a Weed Risk Assessment involves answering up to 49 questions on the specific characteristics of a plant. A Weed Risk Assessment can only be completed after the history/biogeography, undesirable traits and biology/ecology of a plant have been analysed. Assessors use a variety of information sources when conducting an assessment including horticultural texts, published primary literature, reputable internet sources and scientific databases.
Multiple sources of information are generally used to answer a question and conflicting information is addressed accordingly. The Weed Risk Assessment allows for an answer of ‘unknown’ if there is conflicting evidence or there isn’t enough information to answer the question.

How does the department ensure consistency when assessing plant species?

When conducting Weed Risk Assessments, the department ensures consistency by:

  • following the Weed Risk Assessment guidelines. The guidelines help to clarify the Weed Risk Assessment questions and the information required to answer them
  • checking that current assessments are consistent with previous assessments
  • making sure that every assessment is reviewed by another scientist
  • consulting with external experts where appropriate
  • discussing the Weed Risk Assessment guidelines in international forums.

How can I help the assessment process?

Importers can help the department assess plants proposed for importation by completing the New Plant Introduction Form and providing any information on the plant.

How does the system deal with newly described species?

Each Weed Risk Assessment involves answering up to 49 questions on the specific characteristics of a plant. The Weed Risk Assessment system requires responses to a minimum number of questions but allows for knowledge gaps (answers can be ‘unknown’), while still producing an outcome. The ability to generate an answer using only a minimum number of questions increases the system’s predictive power for rare, endangered, recently discovered and little-known species. If the minimum number of questions cannot be answered, the species falls into the ‘further evaluate’ category.

What happens to species that require further evaluation?

Species that require further evaluation of their weed risk to Australia are added to BICON as ‘not permitted entry due to insufficient information’.
When a species requires further evaluation, importers are notified of what information is missing in the assessment.
Importers can request to have these species reassessed if new information becomes available or if the importer has access to information that was not considered in the original assessment.

What does it mean when I am told that the species I want to import doesn’t have a scientifically valid name?

For the purposes of Weed Risk Assessment, the department follows the International Code of Botanical Nomenclature in determining plant names. It is the importer’s responsibility to provide the department with the correct botanical species name.
Botanical species names should be determined from primary botanical sources (i.e. published journal papers describing the species), where possible. Alternatively, reputable secondary sources can be used, such as census lists, flora compendiums or general nomenclature databases including:

When a species name cannot be verified in primary botanical or horticultural sources or through a reputable secondary source, the department informs the importer that the species requested does not have a scientifically valid name. In this case, importers are encouraged to provide information that verifies the species’ name so that an assessment can be conducted.
Name verification is vital to ensure a Weed Risk Assessment is conducted on the actual species being imported and is in line with our international obligations.

How long does it take to assess a species?

The time required to complete each assessment varies depending on how many assessments are requested at any one time and on the plant species itself.
The department places all assessments in a queue and each assessment is done in turn. Importers requesting a large number of assessments are asked to prioritise their assessments so that specific species are assessed first.
If published information on a species is scarce, it may take longer to find all the relevant available material. The time frame may also be affected if officers need to visit or organise loans from other libraries for rare or out-of-print horticultural and botanical references.

Can I conduct a Weed Risk Assessment?

You can do your own Weed Risk Assessment by following the Weed Risk Assessment process. However, all Weed Risk Assessments must be validated by the department. This ensures that the guidelines for Weed Risk Assessments are applied consistently, as required by Australia’s international obligations under the Agreement on the Application of Sanitary and Phytosanitary Measures.

How much does a Weed Risk Assessment cost?

Weed Risk Assessments are funded by the Australian government to ensure Australia is appropriately protected from the introduction of new weed species. There is no cost charged to the applicant.

Does the Weed Risk Assessment system consider the potential benefits of plants proposed for importation?

The Weed Risk Assessment system is used to determine the weed potential of all proposed plant imports, regardless of their end use or potential for economic benefits.
Potential economic benefits cannot be considered in a science-based pest (weed) risk analysis. This is consistent with Australia’s international obligations under the International Plant Protection Convention.

Why are individual species assessed rather than whole genera?

The department conducts weed assessments of plant species rather than assessing whole genera because the international standard considers that ‘the taxonomic unit for a pest is generally species. The use of a higher or lower taxonomic level should be supported by scientifically sound rationale’ (FAO 2016b).
Following the Nairn review of quarantine systems in 1996, Australia moved from a prohibited list to a permitted list at the species level. Genus-level assessments do not take into account the variation of weedy characteristics between species within a genera.

Where can I get additional information?

Information on the Weed Risk Assessment system and electronic versions of the weed risk assessment system can be obtained from Plant Division in the department.


FAO (2016a) International Standard for Phytosanitary Measures No. 5: Glossary of phytosanitary terms. Secretariat of the International Plant Protection Convention, Food and Agriculture Organization of the United Nations, Rome.

FAO (2016b) International Standard for Phytosanitary Measures No. 11: Pest risk analysis for quarantine pests including analysis or environmental risks and living modified organisms. Secretariat of the International Plant Protection Convention, Food and Agriculture Organization of the United Nations, Rome.

Last reviewed: 30 September 2020
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