At least one person has life threatening injuries after a car drove into a group of 20 cyclists in Waikato tonight.

The car hit the cyclists about 6.20pm on Puketaha Rd, Puketaha near Hamilton, said St John spokesman Norm Ngatai.

Four of the cyclists were treated at the scene, and two transported to Waikato Hospital.

"Out of the four, two patients were both taken through to Waikato Hospital, one in a critical condition with life threatening injuries and the other in a serious condition," he said.

A Waikato District Health Board spokeswoman said the cyclists - whose ages and genders were unknown - were still undergoing assessment in the Emergency Department last night.

Mr Ngatai said the accident occurred between Gordonton Rd and Sainsbury Rd.

Three ambulances, an intensive care paramedic and rapid response vehicle attended the incident, he said.

Police were unavailable for comment on the issue.