SYDNEY (AFP) - Australia on Wednesday said it will impose targeted financial sanctions and travel bans against officials involved in the annexing of Crimea, rallying behind allies the United States and the European Union.

While none of the 12 Russian and Ukrainians in the firing line was named, Foreign Minister Julie Bishop said they were "individuals who have been instrumental in the Russian threat to the sovereignty and territorial integrity of Ukraine".

"I condemn in the strongest terms Russian President Vladimir Putin's move to annex the Ukrainian territory of Crimea," she said.

"The unauthorised vote in Crimea on 16 March, carried out while Russian forces were effectively in control of the territory, cannot form the legitimate basis for any alteration of the status of Crimea."

Crimea voted in a referendum on Sunday to break away from Ukraine and rejoin its former political master Russia. Mr Putin on Monday signed a decree recognising Crimea as an independent state.

"The situation in Ukraine remains serious, with the potential for military confrontation," said Bishop.

"We have remained in close contact with friends and allies, including through our membership of the United Nations Security Council, where we have delivered strong protests to Russia about its conduct in relation to Ukraine."

The United States and the European Union slapped sanctions on Mr Putin's inner circle on Monday. Japan and Canada also announced measures.