Wellington, Feb 7 NZPA - The large-scale inquest into the deaths of three-month-old twins Chris and Cru Kahui has been postponed indefinitely, with more time needed to prepare for the investigation.

The South Auckland twins died in Starship Hospital in June 2006 after being admitted with head injuries.

Their father, Chris Kahui, was acquitted of murdering the twins in 2008, after the jury deliberated for only one minute.

His defence was that the twins' mother Macsyna King was the killer but she had never been charged.

The inquest was due to begin on February 22 in Auckland District Court, but that date had been "vacated" and no new date had been set, the Sunday Star Times reported.

A number of groups, including the Ministry of Social Development, two district health boards, the Families Commission and police were to take part in the inquest, along with the Crown, lawyers, Mr Kahui and Ms King.

Authorities were understood to have had trouble finding Ms King, who may be living in Australia, the Sunday Star Times reported.

Chief Coroner Judge Neil MacLean said earlier that the point of an inquest would be to take a wider look at the deaths including how they happened and whether anything could be done to prevent similar deaths in future.

Kahui murder investigation head Detective Inspector John Timms said in October the case was not closed but police had had no new information since Mr Kahui's acquittal.

They would assess any new information from the inquest, he said.