Emergency services are attending a two-car crash at Hamilton's Dinsdale roundabout.

The crash happened at the Whatawhata and Dinsdale Rd intersection just before 2.20pm today.

Waikato Police Senior Sergeant Charles Burgess said the two cars collided at the Dinsdale roundabout.

St John treated one person in a serious condition and two others in a moderate condition. They were all transported by ambulance to Waikato Hospital.