Police have arrested a further 20 people who joined the chained group at the port, charging them with trespass.

The group carried a banner reading "APEC fuelling climate chaos".

Yesterday, a different group of protesters interrupted production at the Loy Yang power station in Victoria's Latrobe Valley, cutting power generation by a quarter when one generation unit was forced to shut down as a safety precaution.

The protest was magnified by the coincidental shutdown of a second unit for maintenance, meaning the total power output was halved until police intervened a removed the protesters who had chained themselves to the coal feeding conveyor belt.

A further 11 protesters were arrested on Sunday morning after painting "Australia Pushing Coal Export" on a coal ship at Newcastle Port.

Sydney police are gearing up for a major protest planned for September 8 through the streets of Sydney surrounding the economic forum.

It is estimated about 10,000 members and supporters of the Stop Bush Coalition will march in Sydney in a peaceful protest.

In the days leading up to APEC, Prime Minister Howard announced climate change was a key issue on the APEC agenda and that $A70.7 million had already been dedicated to climate change initiatives.

APEC organisers are expecting a surge in protest with the arrival of US President George Bush in Sydney tonight.

About 70% of Australia's total international trade is with APEC countries, mainly China, the US, Japan, Korea and New Zealand, at a value of $250 billion in 2006.

APEC countries account for about 64% of Australia's coal export trade.