NSW man arrested over SA assault

South Australian detectives are travelling to NSW to seek the extradition of a 43-year-old man who has been arrested over the sexual assault of a woman in Adelaide three years ago.

The woman was walking through Victoria Park in 2013 when she was grabbed from behind and sexually assaulted, police say.

The initial investigation stalled but police say forensic evidence emerged this year which resulted in the man from northern NSW being identified as a suspect.