Organisers of the G20 summit to be held in Brisbane later this year are closely watching events in Ukraine and the possibility tensions might keep Russian President Vladimir Putin at home.

Mr Putin has attracted international condemnation over his country's incursion into Ukraine's Crimean peninsula.

Vladimir Putin at a press conference in Russia. Credit:AFP

United States President Barack Obama and United Kingdom Prime Minister David Cameron have both threatened non-military retaliation against Russia, while German Chancellor Angela Merkel has reportedly been busy in the background trying to calm down all parties.

All four leaders are due in Brisbane in November, but plans may change if tensions continue to rise.