There are two sides to managing copyright in conference presentations:
Under the Copyright Act1968, using material in a conference presentation without permission from the copyright owner is only allowed in certain circumstances, such as:
In all other circumstances, permission from the copyright owner is required.
If the conference paper or presentation is going to be published, permission or rights to include copyright material in the published version is required.
Regarding copyright in your own original work, the conference organisers will need to get your permission before publishing your paper. They should be able to provide you with a written agreement or consent form, make sure this is read carefully.
For more information, see the Publishing strategy guide:
When presenting at a conference in another country, the copyright laws for that country apply. The conference organisers should be able to provide information on any local copyright restrictions and obligations, and any plans to publish the papers or record the presentations.