Labour says New Zealand soldiers' deaths in overseas battlefields will no longer have independent scrutiny if changes to the Coroners Act go ahead.
Defence spokesman Phil Goff said amendments to the legislation will block a coroner from for launching an inquiry when a New Zealand Defence Force member is killed in hostile action overseas.
The coroner will only be able to report on a soldiers' death if given approval by the Attorney-General, and the coroner cannot make any recommendations after an investigation.
Mr Goff said in a statement: "Having military deaths only investigated in-house raises suspicions that this is a convenient way of closing down investigation and criticism of Government and Defence Force decisions and mistakes."
Mr Goff released advice from officials, who have expressed concerns about the amendment.