Defence Minister Richard Marles is preparing for a protracted conflict in Ukraine as Russian president Vladimir Putin warns of nuclear retaliation if his country's borders are impinged.
Ukraine has retaken ground in the nation's east, forcing a Russia retreat from some previously seized territory.
Russia is attempting to formalise its annexation of parts of Ukraine by holding referendums on separation, which have been labelled a sham and illegitimate by much of the international community.
