Palmerston North police are asking for the public's help after a serious assault on Tuesday evening

A woman was attacked by a man who'd been following her on a bike, while she walked along the Mangaone Stream Walkway, near Amberley Avenue.

He's described as middle-aged, Maori, and wearing dark clothing at the time of the assault.

The woman required medical attention and is recovering at home.

Police want to hear from anyone with any information, and increased patrols are operating in the area.