An anti-war protest in Sydney turned violent on Wednesday, as demonstrators pelted police officers with bottles and furniture.
Wednesday's protest in Sydney was the most violent yet
The trouble began when hundreds of people were refused permission to march through the city centre in protest against Australian involvement in the US-led war in Iraq.
Despite the continuing protests, a recent opinion poll suggests that opposition to the conflict is falling.
Opinion polls published before the war began suggested a majority of people were against attacking Iraq.
One poll conducted on 14-16 March found that 68% of respondents opposed military action if it was not supported by the United Nations.
The latest poll, published by The Australian newspaper on Tuesday, showed that 50% of those questioned now support the war.
Polling experts cautioned that UN involvement was no longer part of the question, which may have distorted results.
Prime Minister John Howard, who has committed 2,000 Australian troops to the US-led force in Iraq, has declined an invitation from US President George Bush to attend a war summit in Camp David with British Prime Minister Tony Blair.
A spokesman for Mr Howard said he would speak to President Bush by telephone whenever needed, and would travel to America at a later date.
Correspondents say Wednesday's protest in Sydney was the most violent yet against.
A police spokesman said at least 12 people were arrested during the day, after violence broke out when two separate groups of
protesters merged outside Sydney's Town Hall.
Some protesters later headed towards the office of Prime
Minister John Howard, where they again began hurling
bottles at police.
Two people - one a police officer - were reportedly injured in the violence.
Protests also took place in Melbourne and Adelaide.