There are numerous options for air travel between Ireland and Australia. All journeys will involve at least one stop and the total travel time door-to-door is well in excess of twenty four hours.
Irish passport holders are required to obtain a visa prior to arrival in Australia for tourist visits of any length. This visa,called an Electronic Travel Authority, can be applied for online. Further information about this and other types of visas can be found on the website of the Australian Embassy in Dublin.
Please note that visa applications from Ireland are dealt with through the Australian High Commission in London.
Australian citizens travelling to Ireland are not required to obtain a visa prior to entry. Stays can be granted to up to 90 days; however, this is at the discretion of the immigration officer at the port of entry.
Travellers in both directions should ensure that their passport is valid for at least six months from their intended date of departure from the country being visited.
Australian High Commission in London
Irish Naturalisation & Immigration Service
Department of Immigration and Citizenship

Click here for information about visiting Ireland.
Read More Here