On Tuesday, antiwar protesters rallied in front of the city's main railway station hours before Bush arrived amid the nation's biggest ever security operation.
"We are here today on the eve of APEC to tell George Bush that he is not welcome, wherever he and his architects of death may travel," said U.S. Iraq veteran Matt Howard in Sydney.
Authorities have erected a 5-km (3-mile) security fence across the central business district to isolate the leaders in the Opera House and nearby hotels. A total of 5,000 police and troops are patrolling the city centre.
Protesters also plan to demonstrate against global warming, human rights abuses in China and nuclear proliferation.
CANDLE-LIT PROTEST
Members of the Falun Gong spiritual movement staged a candle-lit protest when Chinese President Hu Jintao arrived in the mining state of Western Australia on Monday.
"We'll be following him during his stay in Australia," Lucy Zhao, a Falun Gong campaign organiser, said at a small rally.
Although he has made climate change a major issue at APEC, Howard has said there will be no binding greenhouse gas emission targets. Green groups have said APEC will be a failure if the leaders fail to set such targets.
Australian Foreign Minister Alexander Downer said the APEC hosts were looking for a broad-based approach to the issue.
"We will be pressing for a commitment by all APEC economies to the key elements of a genuinely global response to climate change," Downer said in a speech to foreign correspondents.
But some developing countries in the Pacific Rim grouping are uncomfortable that APEC is moving further away from its original mission of focusing on trade and investment.
The United States is pushing for a strong statement from APEC leaders in support of a world trade pact. A draft of the leaders' statement obtained by Reuters said they would pledge to ensure that the Doha round of global trade talks "enter their final phase this year".
