Information and evidence

Before legal action can be considered, it is necessary to have evidence and information about what has happened.

Collecting information

There are several ways to find information.

​Legal information, such as laws and policies that apply to a situation and court decisions, can often be found online.

​Information about decisions which have been taken by a government department, Minister, or other authority can also sometimes be found online. If decisions are not published online, there are two ways to obtain information. First, you can write to the relevant department asking them to provide you with the information. Second, you can consider making a request for information under the Northern Territory Information Act or the Commonwealth Freedom of Information Act 1982. For more information about how to make a freedom of information request, read our Fact Sheets on Access to information. Usually, information about companies (e.g. private developers) is not public and so you may not be able to find out information about a company’s activities unless it is provided voluntarily (for example on a company website).

​The information and evidence that needs to be collected will depend on the type of legal action you wish to take. In order to collect relevant information, consider the following questions:

  • What is the activity you are concerned about? Is this a specific activity or an ongoing activity. When did it start? How long has it been going on?
  • Who is undertaking the activity?
  • Was a decision made by a government authority or minister? If so, what is the decision? When was it made?
  • Who was the decision-maker? This will usually be the minister or government department who has been given the authority to make the decision by law. To find out who the decision maker is for a specific law, you will need to know which law applies to your situation.
  • What information did the decision-maker have when they made their decision?
  • What were the reasons for the decision?

If you are considering judicial review or merits review as a legal challenge, it is important to obtain evidence (usually documents) which shows the decision of the government and the reasons for the decision.

Collecting evidence

Evidence is needed in order to bring a legal action. Evidence must be relevant and reliable to be used legal proceedings.

There are two types of evidence that can be used in courts and tribunals. These are:

  • expert evidence; and
  • witness evidence

The rules of evidence are contained in the Northern Territory Evidence Act and the Northern Territory Evidence (National Uniform Legislation) Act.

Expert evidence

Expert evidence is a type of evidence provided to a court or tribunal by an expert witness.[1]

An expert witness is someone who is regarded as an expert because their education, training, skills or experience means they have more specialised knowledge of a subject than the average person. Usually an expert will hold recognised professional or academic qualifications.

In environmental cases, it may be necessary to instruct an expert to collect physical evidence and analyse it (such as taking samples and testing them), or to perform a site visit, or to review other evidence that has been collected. There are many different types of experts who may give evidence in environmental cases. For example:

  • Ecologists;
  • Hydrologists;
  • Town planners;
  • Arborists (tree consultants); and
  • Cultural heritage experts.

For example, if you were concerned about the impact of pollution on wildlife in a freshwater lake, you might need to instruct a freshwater ecologist to take water samples and analyse whether environmental harm was being caused.

​Usually an expert will provide an “Expert Report” to the court or tribunal. This will be a report that contains their expert opinion on the evidence. Experts usually appear at a hearing and may be asked questions on the contents of their report. Experts are required to be independent (i.e. not personally or professionally involved in the facts of the case).

​As experts are required to present their findings to the court or tribunal, it is important that experts are given accurate instructions on what their role is in the case and what their Expert Report must contain in order to make sure that it will be accepted by the court or tribunal. Experts can be cross-examined on their evidence.

​It is helpful to consider instructing an expert at an early stage of any legal action to make sure that the right evidence is collected. A lawyer can discuss with you whether expert evidence is needed and how to instruct an expert. If you are considering legal action on an environmental matter, please contact the Environmental Defenders Office for help preparing your case.

Witness evidence

Witness evidence is evidence presented to a court or a tribunal by a person who has first-hand experience of something, for example, because they were there at the time something happened and observed it. Witness evidence is presented to a court or tribunal in the form of a witness statement. This is a document that states what that person will say in court. Witnesses can be cross-examined. This means that the other parties can ask them questions about their witness statement. The best witness evidence comes from a reliable witness. A reliable witness is one who has a good memory of what they have witnessed and will tell the truth. In addition to a witness statement, a witness can also present other evidence they collected. Usually, this will be presented in the form of exhibits to a witness statement.​

Other evidence includes:

  • photographs;
  • videos; and
  • field notes, diary entries, or log books.

To make sure that this type of evidence is capable of being used it needs to be relevant, reliable and accurate.

Will evidence be admissible?

Some courts have rules about whether or not evidence can be presented to the court and how it is presented. These are called rules of evidence. In the Northern Territory, the Supreme Court is bound by the rules of evidence set out in the Evidence Act. Some tribunals, such as the Lands, Planning and Mining Tribunal are not bound by the rules of evidence. The Lands and Mining Tribunal Rules allow the Lands, Planning and Mining Tribunal to make any directions it wishes in relation to evidence.


[1] Evidence (National Uniform Legislation) Act ss 79 and 177