A driver and nurse escaped unscathed after an ambulance crashed into a bank in the Waikato.

Emergency services were called to the scene on State Highway 3 a few kilometres north of Otorohanga just before 7am.

St John Communications Manager Mark Tregoweth said there was no patient on board at the time.

The ambulance was carrying a nurse and driver returning to the King Country after dropping a patient off at Waikato Hospital.

It's not known how bad the damage to the ambulance is.