Australian academic job advertisements often ask for candidates to show they can liaise professionally with people in certain other academic roles. What sort of experience or achievements are they looking for?
This one is pretty easy. The requirement that you've mentioned simply asks for some proof, at least, informal one, that a person is capable to successfully facilitate professional interactions by communicating with people from various subject domains and convert ideas and information between domain "languages". In other words, successfully act as a subject domain translator.
The simplest example of such role from the industry would be a business analyst, which most often requires to translate requirements and other project information between business-focused groups and IT-focused ones. Roles of project / product / program manager are related, though different.
Therefore, to meet such requirement, which is very typical for both academia and industry due to their collaborative nature of work, I would say that listing successful projects (with specifying roles and relevant tasks & achievements of facilitating interdisciplinary cooperation) in a CV is enough.
My guess is that the ads mention this because these universities are trying to get more interdisciplinary work going, and they want to hire people to whom interdisciplinary work comes naturally. Also, there's the communication thing that keshlam mentioned.
It couldn't hurt to ask one of the departments who mention this in the ad what they meant by that.
Here are some ideas for things that might support this aspect:
Gave a talk about your work to a non-specialized audience
Published a paper with a colleague from a different discipline
(This one is focused on communication, not interdisciplinary research) Served as peer advisor in such-and-so organization
Served on campus-wide advisory committee on such-and-so topic
In short: soft skills, eloquence, and persuasiveness.
Any certification that involves the above should do the trick. Certification might include English communication certificates, multi-linguistic competence. Other achievements could involve experience as a spokesperson, any role of leadership at your previous institution, or your role as a coordinator in an event such as a conference or a symposium.
This is broadly stated, and as thus, is meant to be broadly interpreted. Some examples that I can think of include:
1) Being able to speak another, or multiple languages
2) Ability to attract industry funding/or attract industry collaboration
3) Versatile and applicable (meaning relevant) research when it comes to getting funding
4) One thing that I cannot stress enough, is that extracurricular activities should not just be thrown out the window. A researcher can show that they have a strong collaboration with K-12 education, for example.
5) The ability to collaborate research with other departments, or schools. How? By demonstrating this, or the willingness to do this, in one's resume (international collaboration is also interesting).
6) If given the opportunity, industry recommendations.
7) Showing a strong commitment to students, and how your research can be relevant to attracting industry and other organizations, to strengthen the department and the employability of the students.
8) Obviously, having a focal research thrust is important, but showing a small bit of diversity, and working with a diverse crowd of professionals on this, shouldn't hut.
9) Having engaged in relevant internships or other work experiences, preferably outside of academia, but relevant to your work.
10) Demonstration of strong interpersonal skills, demonstrated by recommendations.
A couple of the points which I have stated above seem to be quite similar. The reason is, academia loves those who can involve industry. Why? This leads to funding and employability of students. Additionally, the bottom line in academia is funding, and if your bringing in other departments, your going beyond your call of duty. Again, this statement is meant to be broadly interpreted, and there are many other ways that once can demonstrate this.