Police hunt gang after Sydney rampage

A German tourist who was in Australia less than a day is undergoing surgery after being assaulted by a gang behind a string of Sydney robberies and assaults.

The 32-year-old was one of six people attacked by up to four bandits during an hour-and-half cross-city spree in the early hours of Tuesday.

The rampage is believed to have started in West Pennant Hills where the gang stole a white Ford Focus.

About 2.30am, a 39-year-old man was knocked to the ground by members of the gang who stole his wallet, laptop and phone at Parramatta before fleeing in the stolen car, police say.

The group next headed into the city and robbed two women and a man near Hyde Park, assaulted the German tourist in Surry Hills and held-up a convenience store in Glebe.

The 7-Eleven employee was unharmed but has told detectives the three men, who fled with cash and cigarettes, were armed with a machete and hammer.

About 3.40am, a police chase was launched but with the car running several red lights and reaching speeds up to 130km/h, it was called off near Homebush West.

Police say the German man suffered severe facial injuries, a broken jaw and fractured cheekbones and was robbed of his personal belongings.

"It's disgusting and embarrassing for us that somebody comes here from another country and this happens within a day of them being in Australia," Detective Acting Superintendent Sam Crisafulli told reporters on Tuesday.

He described the attacks as cowardly and said he was shocked by the ground covered during the spree.

"I haven't seen anything like this in a long time," Supt Crisafulli said.

"It started at West Pennant Hills then came into the city and then ended up in the western suburbs of Sydney, so they've made a lot of ground overnight."

The car was found at Bidwell, in the city's west, and a crime scene has been established.

The injured man is undergoing surgery at St Vincent's hospital with his family believed to be flying from Germany to be by his side.