Police are hunting for two suspects after four robberies in Sydney's inner west on Saturday, which left one man in a critical condition.

The four separate incidents during the violent crime spree, which occurred between 12.20am and 1.30pm on Saturday, are believed to be linked, according to police.

The first attack occurred when a man was grabbed from behind and assaulted while walking on Arthur Street in Ashfield about 12.20am.

Police are searching for suspects after four violent robberies in the inner west on Saturday.

The 29-year-old man suffered swelling and bruising to his face.