The Chief Archivist is to investigate John Key's deleting of text messages.

The Green Party asked for an investigation to see if the Prime Minister has broken public record laws following admissions made in Parliament that he deletes his texts.

That includes correspondence with blogger Cameron Slater.

Green Party open government spokesman, James Shaw, says the archivist has confirmed she'll look into the Prime Minister's record keeping practices, and whether there's been a breach of the Public Records Act.

Mr Shaw says they believe the text messages should be treated the same as emails or other correspondence.

He says they are public records which should be available to every New Zealander under the Official Information Act.