They are due to appear in Rotorua District Court this afternoon.
The arrests were announced in a press conference at Dunedin Central Police Station fronted by Inspector Shona Low this morning.
The arrest is linked to the discovery of a bloody crime scene in St Clair where police and forensic scientists have worked since Sunday.
Police said in a statement a post-mortem is taking place today and formal identification of the man will be completed later this week.
Police said they were not looking for anyone else in respect of this incident.
"We have received some information regarding this matter from the public and we thank them for their assistance," Low said.
"We are still seeking further information in regard to the dark blue 1995 Toyota people mover that travelled from Dunedin to Picton in the early hours of the morning of Tuesday 5 February."