The Defence Minister says the Army is shamefaced over another missing medals problem at the Waiouru Army Museum.

The Defence Force has confirmed at least two sets of medals, one a donation, are missing from the museum's collection. It is blaming flawed systems. It came to light after a curator was sacked for stealing rifles and other museum pieces.

Defence Minister Wayne Mapp has been told the medals cannot be located.

"Obviously that's deeply embarrassing. Because quite clearly when people give medals to the museum they do so on the basis of trust. And they also do so because the collection itself has got some significance."

Dr Mapp say the Army Museum wants to assure the public precious memorabilia stored at the museum is being properly protected. He says the museum will replace the medals for the families affected.

"But of course they will be replicas. It's not quite the same as receiving the actual medals that your family member received at the end of World War II. It has a different feeling."