01/08/2016 6:09 AM AEST | Updated 01/08/2016 7:00 AM AEST

Police Hunt One Man For 27 Cold Case Sydney Sex Attacks Over 15 Years

DNA tests show same man behind string of offences back to 1985.

NSW Police
Two artist impression images of the man, as released by police

Police believe one man was behind a spree of sex assaults through Sydney's eastern suburbs between 1985 and 2001, and are pleading for help after uncovering what may be one of Australia's worst serial offenders.

NSW Police announced on Monday that they are hunting one man who may be responsible for as many as 27 actual or attempted sexual assaults on women spanning three decades. DNA tests and similar circumstances around the incidents have led police to believe the string of attacks -- in which a knife-wielding man targeted women aged between 14 and 55 through Sydney's east in the 1980s, 90s and early 2000s -- are linked.

Strike Force Doreen was formed in 2005 to investigate five linked sexual assaults, but police say new evidence and investigations saw them expand that strike force to include 27 incidents. DNA tests in Australia and globally have not turned up any leads, so police have made a public plea for assistance by releasing two artist impression images of the man they want to speak to.

"Investigators believe the man would now be aged between 45 and 64, and describe him as being about 160-180cm tall, but more likely to be less than 170cm tall; with a dark complexion, dark, wavy hair; brown eyes, and a broad nose," police said in a statement.

"His physique changed over time, and in the 1980s was described being of a thin build, then in the early 1990s was described as being of a medium build, and in the later 1990s was described as being of an athletic or muscular build."

"He kept his face covered on all occasions, and in most cases, he was dressed in casual clothing, including tracksuits, hooded jumpers, football-style shorts, or singlets. Police were told the man was always either armed with a knife or threatened the presence of a knife, and spoke with an Australian accent."

Sex Crimes Squad Commander, Detective Acting Superintendent Mick Haddow, said police want to speak with anyone who may have lived in the area between 1984 and 2001, and recalls seeing a man matching the description acting suspiciously.

"For more than a decade, Strike Force Doreen detectives have been conducting extensive inquiries, which adds to the work conducted by their colleagues for 20 years prior," Haddow said.

"While we don't believe any further offences have been committed by this man since 2001, we would always remind the community to be vigilant and look out for each other."