A 58-year-old man has been charged after he allegedly hit his colleague over the head with a hammer during a workplace dispute in Sydney’s CBD.

Police said there was an "altercation between two employees" resulting in emergency services being called to the Insurance Australia Group office on George Street in the city at 8.15am on Monday.

Paramedics were called to reports that a 35-year-old man had been hit on the head with a hammer and was bleeding.

He was taken to hospital with head injuries and has been released.