Demonstrators plan to set up a permanent campsite outside the Reserve Bank in Sydney as part of a global day of action inspired by the Occupy Wall Street movement.

Organisers intend to remain camped in Martin Place "indefinitely" from Saturday, as they attempt to spread their pro-democracy, anti "corporate greed" message.

Similar Occupy protests will begin in capital cities across Australia on the same day.

"People are coming with all sorts of reasons to get out on the streets," a spokesman for the Occupy Sydney event told AAP.

"There's a general sense that the world is dominated by the 1 per cent of super rich at the top of society.