Twenty-three people have died in a serious road accident in southern Brazil after a minibus carrying patients collided with a lorry early on Wednesday on a national road in the state of Paraná.

"Preliminary findings suggest that the lorry may have veered into the oncoming lane and collided head-on with the minibus," the news portal "G1" quoted the Brazilian National Highway Police as saying. The exact circumstances are still under investigation.

The accident occurred near Ipiranga in the Campos Gerais region. According to the authorities, 13 women, eight men and two children died. The lorry driver also lost his life. Five people were injured and taken to hospital, according to the Paraná State Secretariat for Public Security.

The minibus reportedly belonged to the health service and was carrying patients to hospitals in the greater Curitiba area, some 200 kilometres away.

The accident site was completely closed off for several hours. The national highway connects several regions in southern Brazil and is, in places, only a two-lane road.

The state government of Paraná has declared three days of mourning.