Man jumps into Sydney Harbour to block ferries before allegedly trying to steal police gun

A man has jumped into Sydney Harbour in the path of ferries and tried to grab a police gun after he was rescued.

Police say the 25-year-old ran from a unit on Macquarie Street where witnesses reported the man had climbed from his balcony onto an awning and down to the footpath about 7pm on Tuesday.

When police arrived, the man ran into the water and swam into the direct path of ferries, ending up near the Opera House.

He was rescued by water police but it's alleged he became violent and tried to grab an officer's gun before jumping back into the water.

Police say they pulled him back onto the boat and he was charged with assaulting police, two counts of resisting arrest and obstructing safe navigation of a vessel.

He was granted conditional bail to appear before Downing Centre Local Court on April 20.