On Saturday, thousands of abortion rights activists holding pink and black placards marched over the Brooklyn Bridge in support of women's constitutional right to have an abortion.
The Republican Party platform supports a constitutional amendment banning abortions.
There were several other protests and at least two people were arrested in a pro-union rally, bringing the number of arrests to 288 since demonstrations began on Thursday.
About 2000 people opposed to the Bush administration's military and diplomatic responses to the 11 September 2001 attacks surrounded the destroyed World Trade Centre site and solemnly rang bells.
"We felt September 11 was being appropriated by Republican spin doctors and they were turning it into a grotesque endorsement of world domination and domestic repression," said demonstration organiser Christian Herold.
The Republican convention to confirm Bush as the party candidate runs between 30 August and 2 September.
The largest anti-Bush demonstration is scheduled for Sunday, when an estimated 200,000 people are expected to march past Madison Square Garden to decry the US-led war in Iraq.
On Friday night, 264 people were arrested when about 5000 cyclists rode through New York streets, some past the convention arena, shouting "No more Bush".