Hamilton Police are investigating a serious, sexually motivated assault in the grounds of Waikato University this morning.

The 20-year-old female victim was confronted and assaulted by a male in the University grounds around the Maths and Sciences faculty at about 8.30am.

She has been punched and dragged into a secluded area where the assault has continued.

The offender has fled after she resisted vigorously and screamed whilst the assault took place. The offender is described as Dark skinned Male aged in his 20s about 160 - 170cm tall 5"6" to 5"9" medium build, shoulder length black hair off his face.

His clothing is described as being dark trousers and shoes and a white long sleeve sweat top with two distinctive black lines down the full length of the sleeves.

If anyone saw a person matching this description or has any information they are asked to call the Hamilton Police or Crimestoppers (0800 555 111) This will be the only release for today.

Source: New Zealand Police.