A tow-truck driver has been arrested after DNA linked him to four sexual assault cold cases, making him a suspect in 20 other rapes over the last three decades.

The 51-year-old was led from a home in Epping, north-west Sydney, in handcuffs at 7am on Thursday after being arrested by detectives from Strike Force Petit.

The Child Abuse and Sex Crimes Squad swooped after new forensic evidence emerged linked four historic rapes in the Ryde area between 1989 and 2007.

Police told reporters on Thursday afternoon the man is expected to be charged with 20 offences against 12 victims aged between 14 and 40.

Police are now reexamining a number of other sex attacks in the area dating back to the 1980s.

The breakthrough came after a review of four cold cases which were previously linked by tendency and modus operandi, police said.

After the man's arrest police executed search warrants at two properties in nearby Ryde and Berrilee.

Strike Force Petit detectives was joined by heavily armed officers from the North West Metropolitan Region Operations Support Group.

The tow-truck driver was escorted down the stairs of his home in handcuffs while wearing his pyjamas, and was taken to Ryde Police Station.

The Child Abuse and Sex Crimes Squad is comprised of detectives who are specially trained to investigate matters against children and adults, including sexual assault, serious physical abuse, and extreme cases of neglect.

The search warrants are still underway and enquiries are continuing.