Three family members - two women and a man - were killed in a two-car collision on the Waikato Expressway last night.

The driver of the car in which the three people were killed was taken to Waikato Hospital in a serious condition, a police spokeswoman told the Herald.

Police say the driver of the other car was alone in the vehicle and was taken to Waikato Hospital in a serious condition.

The crash happened at the intersection of Mangaharakeke Drive and Avalon Drive shortly after midnight.

Police declined to name the three people who were killed, saying next next of kin had not been contacted.

The Serious Crash Unit is investigating the incident.

The road is clear this morning.