Travellers from Down Under have been told to be careful about their security in a sign of the heightened threat.
Earlier this year police said the danger from dissidents was at its worst since the 1998 Real IRA Omagh bomb which killed 29 people.
There have been a series of failed bomb attacks on members of the security forces and one in Lurgan, Co Armagh, this month in which three children were injured.
A statement for the Australian government's Department of Foreign Affairs and Trade said: ''We advise you to be alert to your own security in Ireland.''
The change in advice follows an upsurge in violence at the beginning of the month, which saw a number of bombings and attempted bombings that injured a number of civilians.
The nationalist SDLP has called for MI5 to give up its intelligence role in Northern Ireland, saying it had shown it was unable to protect the population.
